fix: prevent log resolver panic

[davidzhao]

If the room is closed quickly after connect, we could end up with a nil r.room.

[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 64.95%. Comparing base (0460b40) to head (6aa3a76).
Report is 49 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/sip/room.go	40.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #282      +/-   ##
==========================================
- Coverage   65.25%   64.95%   -0.30%     
==========================================
  Files          51       52       +1     
  Lines        6588     7265     +677     
==========================================
+ Hits         4299     4719     +420     
- Misses       1915     2143     +228     
- Partials      374      403      +29     

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[davidzhao]

@livekit/media-devs I'm merging this one. it seems like the right fix.