UI shows gray padlock for encrypted room before joining it

### Steps to reproduce

1. Join a knock-restricted room for an encrypted call
2. Send a knock
3. See a gray, slashed padlock near the top of the screen, suggesting the call is unencrypted
4. Wait to be allowed into the room
5. See that the gray padlock is now green

### Outcome

#### What did you expect?
The padlock should be green from the beginning, or if there is insufficient information for ECall to know whether the call is encrypted, there should be either no padlock or a new icon to indicate an indeterminate encryption status.

#### What happened instead?
The padlock was gray until being granted access to the room, at which point it turned green.

### Operating system

_No response_

### Browser information

_No response_

### URL for webapp

https://call.guest.ess-ecall-poc.ems-support.element.dev/

### Will you send logs?

Yes