RUM-6235 Handle sse request

[xgouchet]

What does this PR do?

This PR Handles properly SSE (Server Sent Event) network request instrumented with our OkHttp interceptor.
In order to report the size of a downloaded resource, we use the peekBody() method which tries to read the whole content of the network request. In case of a SSE request, it would wait until the end of the stream to eventually complete the interception and forward the content to the receiver, blocking the server messages.

ServerSent events should have the text/server-event Mime Type, which we can use to detect such use case.

Motivation

Fixes #2266

[0xnm]

there is one comment about arrayOf -> setOf (performance-wise on such small collection it won't matter though), otherwise lgtm

[mariusc83]

is there a concern if we are using a rc here ?

[xgouchet]

This lib is only used for the sample app, so it's ok

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.90%. Comparing base (949a967) to head (4fc8a54).
Report is 10 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2270      +/-   ##
===========================================
+ Coverage    69.80%   69.90%   +0.10%     
===========================================
  Files          731      731              
  Lines        27156    27160       +4     
  Branches      4572     4575       +3     
===========================================
+ Hits         18954    18985      +31     
+ Misses        6919     6901      -18     
+ Partials      1283     1274       -9     

Files with missing lines	Coverage Δ
...n/com/datadog/android/okhttp/DatadogInterceptor.kt	60.23% <100.00%> (+1.65%)	⬆️

... and 33 files with indirect coverage changes