Invites in room membership list don't local echo (or remote echo).

### Steps to reproduce

1. Go to a room
2. Invite a user to it
3. See absolutely no evidence in the member list that you've invited a user (especially if messages are delayed due to #1105 or bad network connectivity)
4. Feel completely disoriented

### Outcome

#### What did you expect?

You should see a local echo of the invite in the membership list, even if you haven't seen the remote echo of the invite yet. It could have a spinner or be greyed out or something to show that it's still sending.

#### What happened instead?

A feeling of extreme flakiness and nausea.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version

254

### Homeserver

_No response_

### Will you send logs?

No