Fixed LabeledSelect not emitting search explicitly

[eva-vashkevich]

Summary

LabeledSelect wasn't explicitly emitting search event.

Occurred changes and/or fixed issues

Added an explicit search event. It should be working as before.

Technical notes summary

Areas or cases that should be tested

Search should work in anything that uses SelectPrincipal :

• Cluster member editor (Cluster and Project Members -> Cluster membership -> Add),
• Project member editor (Cluster and Project Members -> Project membership -> Add) ,
• Configuring any auth provider (github, azuread, etc)
  or GitPicker (not used in dashboard code)

Areas which could experience regressions

None

Screenshot/Video

Checklist

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
• The PR has a Milestone
• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes

[rak-phillip]

LGTM