linux: Fix IBus in vim mode and some compose state fixes (#12299)

Release Notes:

- N/A

Fixes #12198 and some minor fixes:
* IBus was intercepting normal keys like `a`, `k` which caused some
problems in vim mode.
* Wayland: Trying to commit the pre_edit on click wasn't working
properly, should be fixed now.
* X11: The pre_edit was supposed to be cleared when losing keyboard
focus.
* X11: We should commit the pre_edit on click.

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/gpui/src/platform/linux/wayland/window.rs

@@ -170,6 +170,7 @@ pub(crate) struct WaylandWindow(pub WaylandWindowStatePtr);
 pub enum ImeInput {
     InsertText(String),
     SetMarkedText(String),
+    UnmarkText,
     DeleteText,
 }
 
@@ -448,6 +449,9 @@ impl WaylandWindowStatePtr {
                 ImeInput::SetMarkedText(text) => {
                     input_handler.replace_and_mark_text_in_range(None, &text, None);
                 }
+                ImeInput::UnmarkText => {
+                    input_handler.unmark_text();
+                }
                 ImeInput::DeleteText => {
                     if let Some(marked) = input_handler.marked_text_range() {
                         input_handler.replace_text_in_range(Some(marked), "");