No user feedback when matrix-edited message is not sent to remote due to EditMaxAge

[Petersmit27]

Problem

In Whatsapp, for example, messages can only be edited for 15 minutes after they are sent. Currently, there is no feedback to the user when they edit a "too-old" message in a portal; it is only logged. This could lead them to think the message is edited, but it's not actually edited on the other end of the bridge.

Proposal

• If a user edits an message which is older than RoomFeatures.EditMaxAge, the user should be notified that the message they tried to edit could not be bridged.
• Ideally, the edit should also be reverted, making the chat more aligned with the bridged chat.

See the line where this check is done here: https://github.com/mautrix/go/blob/3048d2edab7a78fc575e523deac4271d257ff889/bridgev2/portal.go#L1278-L1279