chore(local dev): Allow for custom GRPC port to be specified

[NicoHinderling]

I and some other coworkers had an issue where colima was using port 50051, which is the port that taskbroker also wants to use. Changing the port that taskbroker uses caused tasks to start flowing again

This is an attempt to use port 50055 solely in the devservices/local development environment

corresponding taskbroker PR: getsentry/taskbroker#492

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/sentry/conf/server.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #100231   +/-   ##
========================================
  Coverage   81.14%    81.15%           
========================================
  Files        8582      8582           
  Lines      380070    380074    +4     
  Branches    23769     23769           
========================================
+ Hits       308424    308432    +8     
+ Misses      71317     71313    -4     
  Partials      329       329