Replace references to iOS classes with correct Android equivalents.

[plousada]

What does this PR do?

Correct documentation containing references to iOS classes

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

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)

[buraizu]

Thanks, just made some minor suggestions per our contributing guidelines:
https://github.com/DataDog/documentation/blob/master/CONTRIBUTING.md

[codecov-commenter]

Codecov Report

Merging #1012 (5bac997) into develop (0e76b2c) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1012      +/-   ##
===========================================
- Coverage    83.17%   83.13%   -0.03%     
===========================================
  Files          270      270              
  Lines         9213     9213              
  Branches      1464     1464              
===========================================
- Hits          7662     7659       -3     
  Misses        1141     1141              
- Partials       410      413       +3     

Impacted Files	Coverage Δ
...g/internal/domain/event/DdSpanToSpanEventMapper.kt	96.08% <0.00%> (-3.92%)	⬇️
...ain/java/com/datadog/opentracing/PendingTrace.java	56.03% <0.00%> (-2.59%)	⬇️
...ndroid/telemetry/internal/TelemetryEventHandler.kt	90.32% <0.00%> (-1.61%)	⬇️
...rc/main/java/com/datadog/opentracing/DDTracer.java	55.23% <0.00%> (-0.84%)	⬇️
.../android/rum/internal/monitor/DatadogRumMonitor.kt	93.45% <0.00%> (+0.60%)	⬆️
...main/java/com/datadog/exec/CommonTaskExecutor.java	50.00% <0.00%> (+4.17%)	⬆️
...ndroid/core/internal/persistence/file/EventMeta.kt	80.00% <0.00%> (+10.00%)	⬆️