Unread counter shown for thread replies with empty thread list

### Steps to reproduce

1. Be invited to room with prior threads which is set to history visibility from point of invite
1. Await some thread responses in the room

### Outcome

#### What did you expect?

Either be shown the events in the thread list or not be shown that there's an unread (1) but have the message itself hidden

Related to https://github.com/vector-im/element-web/issues/24507

#### What happened instead?


### Operating system

_No response_

### Browser information

_No response_

### URL for webapp

_No response_

### Application version

_No response_

### Homeserver

_No response_

### Will you send logs?

No