Revert "Demote VolumeDialogImplTest#dialogDestroy_removesPostureControllerCallback"

This reverts commit b11a0f22.

Reason for revert: stable when run in marked_flaky suite, which confirms that this is a test interaction issue, but also we have a possible fix now merged, so let's see if that did it.

Change-Id: I463d96a91b8f5f95fbd1229fc164e0d9a64eb6e9