[lib] Do not reset a session when getting already decrypted message

Summary:
https://linear.app/comm/issue/ENG-9713/mitigate-risk-of-olm-already-decrypted-or-keys-skipped

Depends on D13900

Test Plan:
This scenario is hard to reproduce normally (tunnelbroker connection needs to be broken in just the right moment)
so:

• test on both native and web, the steps are the same
• comment out this code: https://github.com/CommE2E/comm/blob/9360b1f7fff5269dd3b56af42dc711045d546cca/lib/tunnelbroker/use-confirm-peer-to-peer-message.js#L39-L43 and this code: https://github.com/CommE2E/comm/blob/9360b1f7fff5269dd3b56af42dc711045d546cca/lib/tunnelbroker/peer-to-peer-message-handler.js#L94
• send a message
• restart/refresh the app

Reviewers: tomek, kamil

Reviewed By: kamil

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D13901