fix attachment URIs change from causing re-render flash

Attachment.uri currently has unstable bits in queryParams, so
exclude them when calculating attachment hash code.

This ensures that a message that goes from sending to sent
doesn't re-render if it has attachments.

Bug: 7434748
Bug: 7426699
Change-Id: I5f9e45bab6f120078c86bd23d271ff69c3350af3
1 file changed