feat: Add source_type when sent from cross platform logs

[fuzzybinary]

What does this PR do?

This will send source_type as a property on error when the attribute _dd.error.source_type is set on the log.

Motivation

The source_type property is not being populated on logs. This isn't too big of an issue as symbolication will default back to source, but there are cases where we'll need the source_type to do proper symbolication.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[codecov-commenter]

Codecov Report

Merging #1895 (5cb4f3e) into develop (9c75335) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1895      +/-   ##
===========================================
- Coverage    83.33%   83.32%   -0.01%     
===========================================
  Files          479      479              
  Lines        16952    16955       +3     
  Branches      2527     2528       +1     
===========================================
+ Hits         14126    14127       +1     
- Misses        2133     2136       +3     
+ Partials       693      692       -1     

Files	Coverage Δ
...in/kotlin/com/datadog/android/log/LogAttributes.kt	0.00% <ø> (ø)
...android/log/internal/domain/DatadogLogGenerator.kt	97.97% <100.00%> (+0.06%)	⬆️

... and 33 files with indirect coverage changes