[RUM 16664] Report TTID and TTFD on RN apps

[sbarrio]

What does this PR do?

TTID reporting

This PR integrates the com.datadoghq:dd-sdk-android-rum-prelaunch module that was added to the Android SDK here: DataDog/dd-sdk-android#3635

This module integrates a way for Cross Platform SDKs to reliably obtain a TTID measurement without having to rely on the native Android SDK being initialized as early as possible, which is something that on most RN apps will not be possible as the first Activity will most probably have rendered its first frame way before the RN bridge has started and the host app has initialized the RN SDK. For more details on the implementation please check the PR linked above.

TTFD reporting

Second, this PR exposes the manual reportAppFullyDisplayed API, which allows for host apps to decide when an app has completed it's first display and report that timestamp back to Datadog to be presented on the Dashboard as the TTFD value for that session alongside its TTID.

Motivation

TTID and TTFD vitals have been reported consistently on native SDKs for a while now but the RN SDK lacked propert support for them. This PR solves this.

Additional Notes

Android

iOS

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• 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)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[sbarrio]

This can be uncommented once the android SDK is updated with a version that includes the prelaunch module.

[datadog-prod-us1-4]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

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