[Status Bar] Don't propagate internally computed disable flags.

The test with the /** Regression test for b/279790651 */ header is a
test that fails without this change and passes with it.

Fixes: 279790651
Test: atest CollapsedStatusBarFragmentTest
Test: verify status bar still hidden on keyguard
Test: verify clock & notif icons hidden when there's a HUN
Test: verify notif icons hidden when there's an ongoing call
Change-Id: I0616d6f4990541397aaed34001b9a471f324064d