[Browser plugin connector] Add session request expiration date

[alexjba]

Description

Summary: This task proposes to add a session request expiration date on each session request. We're already timing out the session request in the backend, but this is not visible to the user.

Acceptance Criteria

1. On each session request the timeout duration is presented to the user in the sign modal, the same way we're showing it for WC
2. The session request cannot be accepted by using the Sign button once it expired
3. The session request cannot be signed once it expired
4. The user is notified when the session request expired