Detect and delete unused code using static analysis

[novocaine]

Your use case

For example - https://camchenry.com/blog/deleting-dead-code-in-typescript

We should consider running this in CI

Have you considered any alternatives?

No response

Additional context

No response

[SimonBrandner]

Doing this for our project is rather tricky as ts-prune doesn't see into the upper layers to check whether or not an export is actually being used. It does check dependencies though, so if we run it in element-web, it will check all the underlying repos. That means that if we want to setup a GHA for this, we will have to clone element-web and all the layers below. This isn't a problem for element-web (surprisingly) and matrix-react-sdk (since we already do this there) though we don't do this in the matrix-js-sdk.

It will probably be necessary to do this in the matrix-js-sdk as not doing it there could result in the CI failing for the other repos but not for matrix-js-sdk itself

[SimonBrandner]

This is blocked on matrix-org/matrix-react-sdk#8612

There are two PRs (matrix-org/matrix-react-sdk#9052 and #22830) which add GHAs for this but are blocked atm. This is because right now we have unused code which will be used by matrix-org/matrix-react-sdk#8612 once merged

[SimonBrandner]

This is now done 🎉