Fix shelf icons when on an external display

The shelf icons were being created with the application context instead
of the display-aware shade context. This caused issues with display
density.

This was not catched from any linter as the way icons are created is very custom (a class that sets fields to a notification entry)

Also, methods to create icons without providing a proper context have been marked as deprecated explicitly: a full cleanup to delete them will foll

Bug: 446842713
Test: IconManagerTest + manually add many notifications while on the external display and observe shelf icon sizing being correct.
Flag: com.android.systemui.shade_window_goes_around
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:9650df1671e712c770b85f865bf6bda01499ca22
Merged-In: Ifcb3c1db7e5bd54e3129d652c2e9eae79595b530
Change-Id: Ifcb3c1db7e5bd54e3129d652c2e9eae79595b530