Remove setDockedStackMinimized credentials prompt

Reverts functional parts of commit 853304c0

This lives in a TaskStackListener now, so we just start the prompt for
activity stacks that need it, not for the whole device at once.

Bug: 31001762
Test: make -j20 && Boot, `adb shell service call trust 6 i32 {userid} i32 1`, resize docked stack.
Change-Id: I58be5174e10779f01149de1cd5c2a4db00b98490