feat(tracing): Make BrowserTracing heartbeat interval configurable

[outsideris]

Close #4925

The heartbeat interval was hard coded.
This PR makes heartbeat interval configurable via BrowserTracingOptions.

[Lms24]

Thanks for opening this PR! On first glance this looks like a good change to me. We should try though to not make this breaking change (see my comment).

Would you mind adding a test that tests a custom heartbeat interval?

Side note:
When we merge this, we'll need to update the BrowserTracing options in docs as well. You obviously don't have to do this but I'm just putting it down here so we don't forget.

[outsideris]

I've made heartbeatInterval optional and add a test.
Please check new test is correct.

[Lms24]

Thanks for adding the test! Looks good to me so far. One small doc change and then I think this is ready to 🚀

[outsideris]

Thank you.

[Lms24]

@outsideris I just noticed that our linter check fails because of format errors in browsertracing.ts. Would you mind running yarn fix in the browser package? yarn lint should give you more insights into what's causing the problem.

[outsideris]

I fixed the lint errors. I missed it when I committed the suggestion on GitHub.

[Lms24]

Thanks @outsideris! The PR looks good to me.

For the team: Let's wait with merging it until have a PR which updates our docs accordingly.

[Lms24]

@outsideris apologies for missing this initially but the startIdleTransaction signature needs to be changed because it's still potentially breaking. Would you mind making this change? If not we can do it too.

Missed breaking change

[outsideris]

I fixed the breaking change and tests as well.

[Lms24]

Thanks @outsideris. Seems like GH Actions have an incident going on which is why CI won't run. Will take a final look tomorrow.

Added a docs PR in the meantime: getsentry/sentry-docs#5606

[outsideris]

I rebased this on latest master.

[outsideris]

I couldn't find why the tests failed. Any hints?

[Lms24]

I couldn't find why the tests failed. Any hints?

Those were just flakes. I re-ran the failed jobs and they passed.