Inject room and attendee into chat notifier

[nickvergessen]

Steps

1. Create 70 users:

i=10
while [ $i -ne 70 ]
do
        i=$(($i+1))
        echo "$i"

	USERID=$(cat /proc/sys/kernel/random/uuid)
	OC_PASS="123456" occ -vvv user:add --password-from-env --display-name "Dummy #$i" -g "dummies" $USERID
	occ -vvv user:setting $USERID settings email "test$i@yourdomain.tld"

done

2. Create a conversation as admin with group "dummies" (and check the database queries of this request)
3. Post a message with @all

Query count

Message	Before	After
chat	16	16
@employee2	23	23
@all	367	90

Compare query log:

[danxuliu]

Import of RoomNotFoundException should be removed in first commit and unit tests need to be fixed in second commit.

Other than the comments, code looks good (but I have not tested it).

[vitormattos]

I tested locally, working fine and get the same reducing of queries.

[nickvergessen]

@danxuliu you fine with this step now?

[nickvergessen]

Just asking because it would be nice to get this in and then continue with #6340

[danxuliu]

I split Vitor's commit in two fixups and added another fixup with the missing changes to the psalm docs.

In the end I did not replace if ($alreadyNotified === $userToNotify) { with if ($alreadyNotified['id'] === $userToNotify['id'] && $alreadyNotified['type'] === $userToNotify['type']) {. As explained, right now it should work fine, so let's adjust it in the future if the order in which the methods are called changes rather than preemptively adjust it now.