[Alerting UI] Index selection popover doesn't close on attempted save

[ymao1]

Kibana version: 7.9

When creating an index threshold alert, if 'Save' is pressed while the index selection popover is open, the popover remains open. This leads to a potentially confusing experience if a confirmation modal opens in response to the 'Save' action. This may be true for other popovers on the flyout as well.

Before hitting save:

After hitting save:

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[mikecote]

To timebox 1hr to see if it's EUI bug (and open issue) or we'll re-triage otherwise.

[ymao1]

I believe this issue is related to this EUI issue: elastic/eui#3172

This issue only occurs when the popover is open and the user is clicked into the EuiSelect "time field" component. It takes two clicks to close the popover when the user is in this state. For this particular issue, if the first click is on the 'Save' button, the save action is triggered, potentially popping up the confirmation modal.

Since this seems to be an EUI bug and there is already an issue open for it, it seems like we can close this issue.

[ymao1]

Issue should be fixed with elastic/eui#3172