Fix to _C filename postfix and change to auto coloring

[SaifKhan21]

@adisidev
This pull request features a fix to one of the project's Github issues along with a change to how auto coloring works:

• Fixes When only one inset is there, no file should have the _C postfix #238: Removes the _C postfix from the filenames if there's only one inset
• Changes how auto coloring works when some but not all regions have specified colors: auto colors all remaining uncolored regions to light gray (#f2f2f2) instead of using the Dark color palette

This PR also includes changes requested by comments from the previous PR (#262), such as:

• Changing the removal of the _C file postfix to now have it return only two SVG files when there's only one inset, the _input file and the _cartogram file
• Reformatting the auto coloring code so that it doesn't run additional unnecessary code when coloring the uncolored regions gray

[github-actions]

🚦 Performance Comparison ^{(α=0.05, ±3%)}

🗺️ Total maps

34

❌ Failed

0

🚀 Speed-ups

0

🐢 Slow-downs

0

⚖️ No change

34

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❌ Failures

None 😎

🚀 Speed-ups (0)

none

🐢 Slow-downs (0)

none

⚖️ No significant change (34)

map	main	pr	Δ %	p
algeria_​by_​wilaya_​since_​2019/​algeria_​population_​by_​wilaya_​2022.csv	2.231±0.007	2.236±0.006	+0.2	0.202
australia_​by_​state_​and_​territory_​since_​1942/​australia_​population_​by_​state_​and_​territory_​2021.csv	0.897±0.005	0.897±0.002	-0.0	0.899
austria_​by_​state_​since_​1945/​austria_​population_​by_​state_​2020.csv	0.394±0.001	0.395±0.001	+0.1	0.545
bahamas_​by_​district_​since_​1999/​bahamas_​population_​by_​district_​2010.csv	3.541±0.028	3.571±0.013	+0.9	0.043
belgium_​by_​region_​simplified_​since_​1995/​belgium_​population_​by_​region_​simplified_​2022.csv	0.170±0.001	0.170±0.001	+0.1	0.380
belgium_​by_​region_​since_​1995/​belgium_​population_​by_​region_​2022.csv	0.177±0.001	0.178±0.001	+0.3	0.230
brazil_​by_​state_​since_​1988/​brazil_​population_​by_​state_​2021.csv	1.566±0.008	1.576±0.015	+0.6	0.209
china_​by_​province_​with_​chinese_​taipei_​since_​1998/​china_​population_​by_​province_​2020.csv	1.500±0.011	1.496±0.005	-0.2	0.499
conterminous_​usa_​by_​state_​since_​1959/​conterminous_​usa_​population_​by_​state_​2020.csv	0.716±0.006	0.714±0.005	-0.4	0.375
contiguous_​usa_​by_​county_​since_​2001/​usa_​population_​by_​county_​2021.csv	45.419±2.451	45.351±1.543	-0.1	0.955
croatia_​by_​county_​since_​1992/​croatia_​covid_​cases_​by_​county_​2022.csv	0.473±0.001	0.474±0.002	+0.2	0.451
croatia_​by_​county_​since_​1992/​croatia_​population_​by_​county_​2021.csv	0.453±0.001	0.453±0.001	+0.1	0.694
egypt_​by_​governorate_​since_​2009/​egypt_​population_​by_​governate_​2017.csv	2.062±0.007	2.057±0.003	-0.2	0.181
england_​by_​region_​since_​2023/​england_​population_​by_​region_​2022.csv	1.352±0.018	1.351±0.013	-0.1	0.923
eu_​by_​country_​until_​2020/​eu_​population_​by_​country_​2021.csv	1.720±0.010	1.749±0.021	+1.7	0.016
eu_​by_​region_​until_​2020/​eu_​population_​by_​region_​2020.csv	6.753±0.033	6.736±0.043	-0.3	0.457
france_​by_​metropolitan_​region_​since_​2016/​france_​population_​by_​metropolitan_​region_​2008.csv	0.483±0.001	0.487±0.004	+0.8	0.057
germany_​by_​state_​since_​1990/​germany_​population_​by_​state_​2011.csv	0.465±0.001	0.466±0.002	+0.2	0.464
indonesia_​by_​province_​since_​2022/​indonesia_​population_​by_​province_​2024.csv	0.687±0.002	0.689±0.002	+0.2	0.169
japan_​by_​prefecture_​since_​1888/​japan_​population_​by_​prefecture_​2020.csv	1.000±0.013	0.986±0.005	-1.4	0.054
malaysia_​by_​state_​since_​2001/​malaysia_​population_​by_​state_​2020.csv	0.571±0.005	0.571±0.002	-0.1	0.886
malaysia_​by_​state_​since_​2001/​malaysia_​population_​by_​state_​2020_​insetted.csv	1.010±0.001	1.013±0.002	+0.3	0.009
metropolitan_​france_​by_​departement_​since_​2015/​metropolitan_​france_​population_​by_​departement_​2022.csv	1.220±0.015	1.208±0.014	-1.0	0.188
russia_​by_​federal_​subject_​since_​2008/​russia_​population_​by_​federal_​subject_​2010.csv	2.938±0.018	2.927±0.018	-0.4	0.321
singapore_​by_​planning_​area_​since_​1999/​singapore_​population_​by_​planning_​area_​2015.csv	3.609±0.007	3.609±0.010	-0.0	0.947
switzerland_​by_​canton_​since_​1999/​switzerland_​gdp_​in_​billion_​chf_​by_​canton_​2019.csv	0.689±0.001	0.692±0.003	+0.3	0.142
switzerland_​by_​canton_​since_​1999/​switzerland_​population_​by_​canton_​2016.csv	0.531±0.002	0.532±0.001	+0.2	0.190
tunisia_​by_​governorate_​since_​1994/​tunisia_​population_​by_​governate_​2014.csv	0.582±0.001	0.583±0.001	+0.2	0.025
usa_​by_​state_​since_​1959/​usa_​population_​by_​state_​2020.csv	1.044±0.004	1.050±0.005	+0.5	0.093
usa_​by_​state_​since_​1959/​usa_​population_​by_​state_​2020_​insetted.csv	0.862±0.001	0.863±0.002	+0.1	0.368
vietnam_​by_​province_​since_​1996/​vietnam_​population_​by_​province_​2019.csv	0.741±0.007	0.739±0.002	-0.2	0.581
world_​by_​country_​since_​2022/​world_​population_​by_​country_​2010.csv	5.503±1.193	6.382±1.629	+16.0	0.313
world_​by_​region/​world_​population_​by_​region.csv	12.341±1.911	11.559±2.147	-6.3	0.520
world_​by_​region_​wo_​antarctica/​world_​population_​by_​region_​wo_​antarctica.csv	6.838±0.056	6.830±0.054	-0.1	0.809