Android Monitoring Doc Edit

[alai97]

What does this PR do?

Removes the view.loading_time metric.

Motivation

#rum-docs, #support-rum Slack

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)

[codecov-commenter]

Codecov Report

Merging #1010 (46f7b1f) into master (c3138f4) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1010      +/-   ##
==========================================
- Coverage   83.13%   83.11%   -0.01%     
==========================================
  Files         267      267              
  Lines        9079     9079              
  Branches     1461     1461              
==========================================
- Hits         7547     7546       -1     
- Misses       1131     1133       +2     
+ Partials      401      400       -1     

Impacted Files	Coverage Δ
...ain/java/com/datadog/opentracing/PendingTrace.java	58.62% <0.00%> (-1.72%)	⬇️
.../android/rum/internal/monitor/DatadogRumMonitor.kt	94.48% <0.00%> (-0.61%)	⬇️
...rc/main/java/com/datadog/opentracing/DDTracer.java	56.07% <0.00%> (ø)
...ndroid/core/internal/persistence/file/EventMeta.kt	80.00% <0.00%> (ø)
...droid/rum/tracking/ActivityViewTrackingStrategy.kt	88.46% <0.00%> (+1.92%)	⬆️
...android/log/internal/logger/TelemetryLogHandler.kt	100.00% <0.00%> (+25.00%)	⬆️