This reverts commit 9e89a175.

Private mode search with suggestion onboarding was overlapping "This time, search with: " text. Adjust constraints to allow it to show under onboarding when present.

This change switches to using python scripts directly in a-c and a-s repositories, which achieves two things:
- we avoid overhead of running through a-c and a-s gradle's build phases, which is quite significant
- all of the logic for checking if projects are up-to-date or need to be republished now lives in those projects

End result is that local fenix builds now incur zero costs if there are no changes in a-c or a-s,
and if there are _any_ changes at all, the corresponding project is reliably recompiled and republished.

This may have minor performance improvements.

I don't see any value in hoisting all dependency versions so I removed
it for this dep. I also see an additional downside (additional indirection to
find values in addition to the indirection of storing all the dependencies in
a single file).

See https://github.com/mozilla-mobile/fenix/issues/4046 for a detailed discussion of this.

In short, this patch removes code that would conditionally hide desktop bookmarks depending
on the signed-in state of the browser.

Setting the `navigationBarColor` is done in the ThemeManager for the
attached activity. Since the migration UI is separate from that, we did
not get this for free.