Fix incorrect double registration when opening editors

Ensures that the editor listeners are only registered once when the editor is created. IdeaVim uses two different events to track editor creation, to try to understand how the editor is being created (new window, split, preview, etc.) and this can lead to calling the `EditorListeners.add` method twice. This would create a second `Disposable` and cause handlers to leak. This is most visible when creating the first window and then disabling IdeaVim. This window would still handle drag events like IdeaVim, even changing the caret back to block after the drag finishes.

src/main/java/com/maddyhome/idea/vim/listener/VimListenerManager.kt

@@ -91,6 +91,7 @@ import com.maddyhome.idea.vim.helper.moveToInlayAwareOffset
 import com.maddyhome.idea.vim.helper.resetVimLastColumn
 import com.maddyhome.idea.vim.helper.updateCaretsVisualAttributes
 import com.maddyhome.idea.vim.helper.vimDisabled
+import com.maddyhome.idea.vim.helper.vimInitialised
 import com.maddyhome.idea.vim.newapi.IjVimEditor
 import com.maddyhome.idea.vim.newapi.InsertTimeRecorder
 import com.maddyhome.idea.vim.newapi.ij
@@ -276,6 +277,11 @@ internal object VimListenerManager {
       // editor's disposable individually.
       val disposable = editor.project?.vimDisposable ?: return
 
+      // Protect against double initialisation
+      if (editor.getUserData(editorListenersDisposableKey) != null) {
+        return
+      }
+
       val listenersDisposable = Disposer.newDisposable(disposable)
       editor.putUserData(editorListenersDisposableKey, listenersDisposable)
 
@@ -468,6 +474,9 @@ internal object VimListenerManager {
         (it.fileEditor as? TextEditor)?.editor?.let { editor ->
           if (vimDisabled(editor)) return@let
 
+          // Protect against double initialisation, in case the editor was already initialised in editorCreated
+          if (editor.vimInitialised) return@let
+
           val openingEditor = editor.removeUserData(openingEditorKey)
           val owningEditorWindow = getOwningEditorWindow(editor)
           val isInSameSplit = owningEditorWindow == openingEditor?.owningEditorWindow