osc2_scenario: Fix SyntaxWarnings

[wentasah]

Checklist:

• Your branch is up-to-date with the master branch and tested with latest changes
• Extended the README / documentation, if necessary
• Code compiles correctly and runs
• Code is formatted and checked with Utilities/code_check_and_formatting.sh
• Changelog is updated

Description

This fixes warnings like the one below:

.../srunner/scenarios/osc2_scenario.py:515: SyntaxWarning: invalid escape sequence '\W'
expression_value = re.split("\W+", option)

These were introduced in Python 3.12. See https://docs.python.org/3.12/reference/lexical_analysis.html#escape-sequences.

Where has this been tested?

• Platform(s): Linux
• Python version(s): 3.12
• Unreal Engine version(s): 4.26
• CARLA version: 0.9.15

Possible Drawbacks

Hopefully none. r-strings are available even in Python 2.6, so this should work even with older Python versions.

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This change is 

[Daraan]

LGTM, I am no maintainer though. Raw strings are indeed already present in Python2 and \W is not a escape sequence recognized by python.

I would encourage their usage for regex much more as it helps to avoid mistakes and future compatibility.