Mumble fixes

[kaitlynia]

Fixes Mumble plugin, wasn't working before. Also scales the distances so that they are usable for Mumble's defaults.

Checklist

• Tested the change ingame
• Provided screenshots if it is a visual change
• Tested in combination with possibly related configuration options
• Written a unit test (especially base/) or added coverage to integration test
• Considered possible null pointers and out of bounds array indexing
• Changed no physics that affect existing maps
• Tested the change with ASan+UBSan or valgrind's memcheck (optional)
• I didn't use generative AI to generate more than single-line completions