Write null into file ID when removing photo

Writing null into the file ID of the photos value delta
'after' will prevent the editor from trying to read it after a
rotation.
Have the photo editor view hold on to the MaterialPalette so we
use the same color for the default once a photo is removed.

Test: Manual usage of removing a photo from a contact with one and
rotating.

Bug: 25978539

Change-Id: I84c4b22c4064de1d788b08921a5c0164475865af
2 files changed