audio policy: fix capture policy for assistant when running as top

Under regular circumstances, an app with the assistant role should
be applied the same concurrent capture policy as any other app.

Current implementation would apply more restrictions to an assistant than
to a regular app when running as top.

Bug: 355644902
Flag: EXEMPT bug fix
Test: regression for various audio capture scenarii
Change-Id: Ifd12ea4590ebbdc9224ce1f2142ffb33da5ac002