Fix crash on easter egg debug mode

Because we use Androidx Toolbar so Activity.getActionBar will get null.
It should use getSupportActionBar but this function only implement on
AppCompatActivity and this need more change.
Remove the set color call to prevent crash first and update the status
bar color to suitable one.

Fix: 141465269
Test: manual
Test: atest DocumentsUIGoogleTests
Change-Id: Ib23e0e46fec29b1079e053921bbd88e84ac8fdb2