feat(profiling): Export start/stop profile session

[Zylphrex]

Need to export these explicitly so it can be used.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.57%. Comparing base (a3b6e5d) to head (69b3c8a).
Report is 1 commits behind head on master.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4079   +/-   ##
=======================================
  Coverage   79.57%   79.57%           
=======================================
  Files         140      140           
  Lines       15512    15512           
  Branches     2628     2628           
=======================================
+ Hits        12343    12344    +1     
  Misses       2335     2335           
+ Partials      834      833    -1     

Files with missing lines	Coverage Δ
sentry_sdk/profiler/__init__.py	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes