Draft: InputMethod: Add a resize event for input panels

This adds support for a new "configure" event in input-panel-v1 that allows resizing the input panel client. This is needed to properly place the input panel when it is used as a "toplevel" type.

The protocol change for this is at https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/146

Draft because it requires protocol changes and it currently breaks the slidingpopup effect for the input panel.