Minor performance optimization during serialization into JSON format

[0xnm]

What does this PR do?

I noticed a small issue in the related code: since JsonArray actually implements Iterable, is JsonArray branch will never be executed, because it goes after is Iterable branch.

By moving is JsonArray up we skip useless toJsonArray call which will create new object and copy elements there from the old object.

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 #1066 (9b7d7a7) into develop (36fb6d6) will increase coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1066      +/-   ##
===========================================
+ Coverage    83.24%   83.26%   +0.02%     
===========================================
  Files          272      272              
  Lines         9279     9279              
  Branches      1494     1494              
===========================================
+ Hits          7724     7726       +2     
+ Misses        1140     1138       -2     
  Partials       415      415              

Impacted Files	Coverage Δ
...ndroid/core/internal/persistence/file/EventMeta.kt	80.00% <0.00%> (-10.00%)	⬇️
...ain/java/com/datadog/opentracing/PendingTrace.java	57.76% <0.00%> (-0.86%)	⬇️
...android/rum/internal/ndk/DatadogNdkCrashHandler.kt	88.11% <0.00%> (-0.54%)	⬇️
...rc/main/java/com/datadog/opentracing/DDTracer.java	56.07% <0.00%> (+0.42%)	⬆️
...tadog/android/core/internal/net/CurlInterceptor.kt	83.33% <0.00%> (+2.38%)	⬆️
...id/webview/internal/rum/WebViewRumEventConsumer.kt	86.05% <0.00%> (+9.30%)	⬆️

[mariusc83]

Good catch !!