feat(spotlight): Add info logs when Sentry is enabled

[BYK]

This came as user feedback (getsentry/spotlight#543). Intentionally not making this part of Sentry logging as I think if one is enabling Spotlight, they should be seeing this in their logs, regardless of their SENTRY_DEBUG setting, which tends to be noisy.

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.

Project coverage is 84.37%. Comparing base (e28dcf6) to head (cbdc15f).
Report is 1 commits behind head on master.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/spotlight.py	85.71%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3735      +/-   ##
==========================================
+ Coverage   84.33%   84.37%   +0.03%     
==========================================
  Files         136      136              
  Lines       14367    14370       +3     
  Branches     2417     2417              
==========================================
+ Hits        12117    12125       +8     
+ Misses       1497     1495       -2     
+ Partials      753      750       -3     

Files with missing lines	Coverage Δ
sentry_sdk/spotlight.py	68.11% <85.71%> (+1.44%)	⬆️

... and 4 files with indirect coverage changes