fix(MSC3911): Use different state retrieval function for graceful handling of missing state

[jason-famedly]

Using the StorageController.state.get_state_for_events() function has a limitation, in that outlier events or filtered events will raise a RuntimeError. This appears to have been intended behavior, as other places this is called filter out events like outliers ahead of time which is the error's normal trigger.

In our case, we are filtering for an extremely narrow set of two types of events, history visibility and a membership event of a user. This can sometimes lead to a situation where the state of the room returns nothing and crashes.

The prime example that exposed this was attempting to get the state of a room's second user and the history visibility event at the point in the state of the room of the creator's initial membership event. Neither of the sought events can exist at that point, hence an error.

Now will use a more tolerant way of dealing with state that can not exist

[nico-famedly]

I'm not super sure, if this is the best way to handle this, but I think it is sufficient, since the media visibility checks are just in addition to already having to receive the media, so having it possibly slightly more lax is probably okay.