It's possible to attempt to add rooms to a space where you don't have permissions to do so

### Steps to reproduce

1. After pressing the four-squares button, and selecting an Item from the list, I am looking at a space.
2. I tap the name of the space (shown at the top, above the list of rooms in that space)
3. I see a popover with "invite people", "explore rooms", "members", "leave"
4. I tap "explore rooms"
5. I scroll to the bottom, a round plus button is displayed in the right bottom corner
6. I tap that button
7. I see a choice: "Create New Room" (sic), "Add existing rooms", "Add space"
8. I tap "Add existing rooms"
9. I see a list of rooms that I am joined to, with check boxes on the right
10. I tap one or more checkboxes, they are marked
11. I press "Save" in the top right corner
12. nothing happens, the menu does not close, there is no error message, no change of colours to a red error colour, the checkboxes continue to be checked

**Edit by Kat:**
> 1. Go to a space where you don't have permissions to add rooms
> 2. Click on space name at the top
> 3. "Explore rooms" in the bottom sheet that pops up
> 4. Note that there is no + button bottom right
> 5. Scroll the Explore rooms list
> 6. See the + button appearing
>
> That + button should not appear after scrolling

### Outcome

#### What did you expect?

Either the menu closes and I have successfully added a room to the space, or I see an error message.

#### What happened instead?

Nothing

### Your phone model

Fairphone 3

### Operating system version

Android 11

### Application version and app store

Element 1.5.25 [40105250] (F-f74a885a), 1.5.25 (f74a885a), from F-Droid

### Homeserver

matrix.org

### Will you send logs?

Yes

### Are you willing to provide a PR?

No