fix: focus for autohideable flyouts

[maribethb]

The basics

• I validated my changes

The details

Resolves

Fixes issue with autohideable flyouts. See #8920 (comment)

Proposed Changes

Uses the IAutoHideable interface instead of doing an instanceof Flyout check.

Reason for Changes

• Using our base Flyout class is not required, only using the Flyout interface is required. We still want to hide autohideable flyouts that don't use our base class, so use the interface to check.

Test Coverage

Documentation

Additional Information