CallStyle: Handle null icon to glue

Bug: <329288442>
Flag: ACONFIG com.android.systemui.new_call_style_action_layout NEXTFOOD
Test: manual
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:19c7dd73f4d7f61e5858241c4c75dbd45722c779)
Merged-In: I5e8b1bae7977f53ce8dd977d17231ec44268c486
Change-Id: I5e8b1bae7977f53ce8dd977d17231ec44268c486
24D1-dev is based on 24Q2-release. Therefore, we merged this CL to 24D1-dev.