RustMatrixRoom is created multiple times when entering the room

### Steps to reproduce

Just entering any room after app launch. The `RustMatrixRoom` is created multiple times for the same `roomId` and `sessionId` when entering the room which leads to flows being subscribed multiple times without releasing the resources.

### Outcome

#### What did you expect?
The room should be created only once, or all resources should be cleaned up and scopes canceled before recreating a new instance.

#### What happened instead?
The `RustMatrixRoom` is created multiple times when entering the room, which leads to flows being subscribed multiple times without releasing the previously allocated resources.

2025-04-09 22:56:21.362 11597-11665 org.matrix.rust.sdk     io.element.android.x.debug           I  elementx: Room_debug_tag, RustMatrixRoom init[thread=DefaultDispatcher-worker-9] | RustMatrixRoom.kt:204

2025-04-09 22:56:21.370 11597-11597 org.matrix.rust.sdk     io.element.android.x.debug           D  elementx: Room_debug_tag, RustMatrixRoom combine flow onStart, thread=main | RustMatrixRoom.kt:220

2025-04-09 22:56:21.527 11597-11597 org.matrix.rust.sdk     io.element.android.x.debug           D  elementx: Room_debug_tag, RustMatrixRoom membershipChangeEventReceived flow onStart, thread=main | RustMatrixRoom.kt:209

2025-04-09 22:56:21.812 11597-11658 org.matrix.rust.sdk     io.element.android.x.debug           I  elementx: Room_debug_tag, RustMatrixRoom init[thread=DefaultDispatcher-worker-5] | RustMatrixRoom.kt:204

2025-04-09 22:56:21.996 11597-11597 org.matrix.rust.sdk     io.element.android.x.debug           D  elementx: Room_debug_tag, RustMatrixRoom combine flow onStart, thread=main | RustMatrixRoom.kt:220

2025-04-09 22:56:22.080 11597-11597 org.matrix.rust.sdk     io.element.android.x.debug           D  elementx: Room_debug_tag, RustMatrixRoom membershipChangeEventReceived flow onStart, thread=main | RustMatrixRoom.kt:209  

### Your phone model

Plain Android Studio Emulator

### Operating system version

Android 15

### Application version and app store

The latest version from develop (25.04.0)

### Homeserver

_No response_

### Will you send logs?

No

### Are you willing to provide a PR?

No