Add ReplayManager.triggerReplay

[waltjones]

Description of the change

Adds triggerReplay method to ReplayManager, with different requirements than the occurrence-centric capture and sendOrDiscardReplay.

• Initiates send immediately after export, and therefore awaits export.
• Tolerates triggering before the recorder is ready, so that postDuration triggers work when triggered at code init.
• triggerReplay is async so that it can be non-blocking for the caller and also return the replayId when it succeeds.
• Doesn't use occurrence-based _canSendReplay.

There may be an opportunity to refactor triggerReplay and capture to use more shared code. This PR doesn't attempt to solve that. It enables the needed triggers in the short term, allowing more time to consider a preferred refactoring.

Type of change

• New feature (non-breaking change that adds functionality)

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development