Update xterm to latest version

[sdirix]

We're using xterm within terminal widget. We're currently still consuming the latest 4.x version however 5+ is released for almost a year now. It contains many improvements, for example fixes for blurred rendering which are affecting the community.

Therefore it would be nice to update the xterm dependency to the latest one. Note that it's not sufficient to only increase the version numbers as there are some breaking changes, at minimum at the typing level.

[msujew]

This will be addressed by https://github.com/eclipse-theia/theia/pull/12691