Fix MNMG Louvain tests on Pascal architecture

[ChuckHastings]

MNMG Louvain uses a feature not supported on Pascal. This PR updates the python unit tests so that it expects an exception to be raised if running on a Pascal GPU.

[afender]

👍

[codecov-io]

Codecov Report

Merging #1322 (db777e3) into branch-0.18 (d69cff7) will decrease coverage by 0.15%.
The diff coverage is 23.07%.

@@               Coverage Diff               @@
##           branch-0.18    #1322      +/-   ##
===============================================
- Coverage        60.21%   60.06%   -0.16%     
===============================================
  Files               67       67              
  Lines             3049     3060      +11     
===============================================
+ Hits              1836     1838       +2     
- Misses            1213     1222       +9     

Impacted Files	Coverage Δ
python/cugraph/utilities/utils.py	66.92% <18.18%> (-4.63%)	⬇️
python/cugraph/dask/common/mg_utils.py	37.50% <50.00%> (ø)

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[ChuckHastings]

rerun tests