Move DarkIconDispatcher into SystemUIPhoneDisplaySubcomponent

This also fixes a race that causes a crash, when DarkIconDispatcher
was requested shortly after a display being removed.

Test: Build & Run
Test: atest SystemUITests
Flag: EXEMPT Dagger change that can't be flagged
Fixes: 428645099
Bug: 417927751
Change-Id: I9866880c1a5b6300fbe1ff1c943849c8f0a56f0f