Refactor broken site report message handlers

[sammacbeth]

Reviewer:

Description:

Some breakage reports were coming through with config version undefined on Firefox (https://app.asana.com/0/0/1209244730607066/f). This is likely caused by a race condition in the breakage report flow if the background is not fully loaded yet.

To fix this, this PR:

• Moves the sendBreakageReport function to a component.
• Removes static access to page context information, using components instead.
• Allows us to wait for the correct config lifecycle event before getting config version.
• Updates the toggle reports component to use this new entrypoint for sending reports.

Steps to test this PR:

Automated tests:

• Unit tests
• Integration tests

Reviewer Checklist:

• Ensure the PR solves the problem
• Review every line of code
• Ensure the PR does no harm by testing the changes thoroughly
• Get help if you're uncomfortable with any of the above!
• Determine if there are any quick wins that improve the implementation

PR Author Checklist:

• Get advice or leverage existing code
• Agree on technical approach with reviewer (if the changes are nuanced)
• Ensure that there is a testing strategy (and documented non-automated tests)
• Ensure there is a documented monitoring strategy (if necessary)
• Consider systems implications

[kzar]

Overall I like the changes, but can we split the race condition fix out from the refactor? Also, I'd like to avoid weakening the ToggleReports unit tests.