Add Storybook story for testing strict mode

[havardholvik]

We have some issues with our useRoomConnection hook lifecycle. Add separate story enforcing strict mode to allow for easy debugging.

Tested like

1. STORYBOOK_ROOM=<your room url> yarn storybook
2. Open "RoomConnectionStrictMode" story
3. Verify you get "Trying to join when room state is already connecting" in console

[nandito]

I see the expected message in the console in canvas view. It joins the room in Docs view, but I guess it disables the StrictMode in that mode.