Mark shade header system icons as not clickable in non-large screen shade

The new system icons container was prompting TalkBack users to activate it, when doing so does not have any effect.

Bug: 297472710
Test: walked through TalkBack to verify the system icons are read out without activation prompt
Change-Id: Ib4f49d67b9864271153d3cb26e1863e0bdc77634
1 file changed