fix(alerts): avoid race condition in anomaly detection requests

[natemoo-re]

Reported bug was that some requests to Seer from the UI did not include config.sensitivity and config.expected_seasonality. Because this was an intermittent, I suspected a race condition.

After digging into the logic more, I noticed one spot where fetchAnomalies() could potentially be called before the component's state changes had been synchronized.

The fix, as in other places, is to defer fetching until the state changes have been flushed by passing () => this.fetchAnomalies() as the second callback argument to this.setState.

I'm very eager to get rid of this class component and eliminate this class of bug 😄👍

Closes getsentry/seer#2141

[saponifi3d]

it'd be nice to also include a unit test for the error to ensure we avoid this specific case in the future.

[natemoo-re]

Just went to add a test but hit some old bugs in the accessibility of our RadioGroup component that made it impossible to query the Anomaly Detection radio option...

sentry/static/app/components/forms/controls/radioGroup.tsx

Lines 76 to 79 in 255e471

	// TODO(epurkhiser): There should be a `name` and `label` attribute in
	// the options type to allow for the aria label to work correctly. For
	// now we slap a `toString` on there, but it may sometimes return
	// [object Object] if the name is a react node.

Will have to fix this another time.