Don't mark read notifications as unseen
Don't mark read notifications as unseen

If a notification is already read it is by definition seen. Don't
mark those as unseen. This can actually happen if our seenTime is
invalid (like a cache miss)

Change-Id: Id943691599116597b6c68d2cc40e7b89a25ce05e

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo