uberf-7755: fix image toolbar visibility (#6208)

Signed-off-by: Alexey Zinoviev <alexey.zinoviev@xored.com>

plugins/text-editor-resources/src/components/CollaborativeTextEditor.svelte

@@ -416,6 +416,7 @@
             toolbar: {
               element: imageToolbarElement,
               boundary,
+              appendTo: () => boundary ?? element,
               isHidden: () => !showToolbar
             }
           }

plugins/text-editor-resources/src/kits/editor-kit.ts

@@ -41,6 +41,7 @@ export interface EditorKitOptions extends DefaultKitOptions {
     toolbar?: {
       element: HTMLElement
       boundary?: HTMLElement
+      appendTo?: HTMLElement | (() => HTMLElement)
       isHidden?: () => boolean
     }
   })
@@ -232,7 +233,10 @@ async function buildEditorKit (): Promise<Extension<EditorKitOptions, any>> {
                 if (this.options.image?.toolbar !== undefined) {
                   imageOptions.toolbar = {
                     ...this.options.image?.toolbar,
-                    tippyOptions: getTippyOptions(this.options.image?.toolbar?.boundary)
+                    tippyOptions: getTippyOptions(
+                      this.options.image?.toolbar?.boundary,
+                      this.options.image?.toolbar?.appendTo
+                    )
                   }
                 }