fix PC timeout when connecting with can_subscribe=false

[s-hamdananwar]

When a participant connects with canSubscribe=false in their token, the server sends subscriber_primary=false in the JoinResponse and does not send a subscriber offer. This results in wait_pc_connection timing out as it is expecting a subscriber PC even when the peer connection is publisher primary. This PR will skip waiting for subscriber PC when subscriber_primary=false.

[xianshijing-lk]

@s-hamdananwar , nice, could you please use codex or claude to add an unit tests in Rust SDK's peer connection tests ?
Ideally, we can verify that things are broken before this PR, and get fixed by this PR.

[s-hamdananwar]

@xianshijing-lk done ✅

[xianshijing-lk]

lgtm, thanks for fixing it.