Fix breadcrumb sorting

[sentrivana]

• ignore errors while breadcrumb sorting
• best-effort coerce string timestamps into datetimes before sorting

Fixes #3508

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.73%. Comparing base (0fb04be) to head (e296589).
Report is 1 commits behind head on master.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/scope.py	71.42%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3511      +/-   ##
==========================================
+ Coverage   79.68%   79.73%   +0.05%     
==========================================
  Files         136      136              
  Lines       14666    14677      +11     
  Branches     3080     3082       +2     
==========================================
+ Hits        11686    11703      +17     
+ Misses       2139     2134       -5     
+ Partials      841      840       -1     

Files with missing lines	Coverage Δ
sentry_sdk/utils.py	83.31% <100.00%> (+0.10%)	⬆️
sentry_sdk/scope.py	84.92% <71.42%> (-0.17%)	⬇️

... and 5 files with indirect coverage changes

[antonpirker]

Nice! Thanks for fixing this!