Revert "Always report mandatory insets for button nav"

This reverts commit 4304a142.

Reason for revert: Likely culprit for b/343564388  - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.

Change-Id: Ibc6fae27f31bcb54406da013babc76b2d5fc7f10