Ros2 humble - remaining flatland_server tests

[JoaoCostaIFG]

• Finished the migration to ros2 of the remaining flatland_server tests
• Fixed a problem on YamlPreprocessor: get_parameter usage changed
• Fixed some integer comparison problems in tests: comparing integers of different sizes
• Added a translation of flatland_server's launch file to the new/recommended python syntax
• Removed the remaining, unused test launch files

[JoaoCostaIFG]

The pipeline test that failed appears to be related to the system's liblua version:

• With liblua 5.1 the result is 223.0
• With liblua 5.3 the result is 223

My friend's system has liblua 5.3, so they changed the test (everything seemed fine). The lua-dev dependency of flatland_server is liblua 5.1, so we'll change it back.

[josephduchesne]

Thanks for this contribution. The changes look good and CI is happy :)