Ignore sender keys in encrypted events

[emmaburton1]

Your use case

What would you like to do?

Update the web client to be compatible with the new Cross Domain Gateway (CDG) currently under development.

Why would you like to do it?

To support an ongoing public-sector project.

How would you like to achieve it?

For clients to work with the CDG, they need to stop using the event.content.sender_key param. It should only be being used to store/lookup the crypto sessions, where they can use the session ID instead.

Have you considered any alternatives?

No response

Additional context

The target delivery date for this project is the end of January, but there's some flexibility if that isn't possible.

Talk to @emmaburton1 for more context on the project schedule and priority.

[emmaburton1]

On second thoughts: This need an MSC before it can sensibly proceed.

So blocked for now.