[Poll] Warning message on decryption failure of some events

[mnaturel]

Your use case

What would you like to do?

When at least one related event (m.reference relation type) to a given poll cannot be decrypted, the associated message contain a warning message saying the result may be inaccurate.

Why would you like to do it?

A poll message is an aggregation of multiple events. It means when some events fail to be decrypted, we may end up with inaccurate results.

How would you like to achieve it?

The message content should be “Due to decryption errors, some votes may not be counted”. The warning message replaces the vote status message at the bottom only when we display results i.e. when the poll is ended or when this is an open poll and current user has voted.

Have you considered any alternatives?

No response

Additional context

No response

Are you willing to provide a PR?

Yes