Ability to jump between messages sent by a given user

### Your use case

#### What would you like to do?

I want to skip through a room's history to try to find what conversations a given user (typically myself) were participating in. For instance, right now I want to skip through my conversations in Element Web Internal to find when i last reported a given bug.

#### How would you like to achieve it?

Having a "skip to previous message sent by this user" would be one way, similar to how we already have "skip to most recent message sent by this user".

### Have you considered any alternatives?

Another option would be to have search support searching by sender, which would give the same effect (and should already be supported serverside API; would just need search UX)

### Additional context

_No response_