ref(tracing): Use float for sample rand

[sentrivana]

Closes #4270

[codecov]

Codecov Report

❌ Patch coverage is 62.50000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.12%. Comparing base (1804955) to head (7c10d00).
⚠️ Report is 6 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/utils.py	20.00%	3 Missing and 1 partial ⚠️
sentry_sdk/tracing_utils.py	80.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4677      +/-   ##
==========================================
+ Coverage   85.07%   85.12%   +0.04%     
==========================================
  Files         156      156              
  Lines       15984    15988       +4     
  Branches     2718     2718              
==========================================
+ Hits        13598    13609      +11     
+ Misses       1600     1593       -7     
  Partials      786      786              

Files with missing lines	Coverage Δ
sentry_sdk/tracing.py	86.61% <100.00%> (-0.03%)	⬇️
sentry_sdk/tracing_utils.py	88.21% <80.00%> (-0.39%)	⬇️
sentry_sdk/utils.py	88.11% <20.00%> (-0.41%)	⬇️

... and 3 files with indirect coverage changes