fix(editor): fix overlay of tool is not shown or repeated when switching tool (#11575)

Close [BS-3029](https://linear.app/affine-design/issue/BS-3029/frame-里面的-shape-没办法进入文本编辑模式)
Close [BS-3082](https://linear.app/affine-design/issue/BS-3082/按s切换至shape工具，在白板上点击会创建两个shape)
Close [BS-3091](https://linear.app/affine-design/issue/BS-3082/按s切换至shape工具，在白板上点击会创建两个shape)

## Fix Shape Tool Issues

This PR addresses several issues with the shape and mindmap tools functionality in the editor:

1. **Fix text editing after mode switching**: Resolves an issue where users couldn't edit text in shapes after switching editor modes. The fix ensures the edgeless block is properly retrieved when double-clicking on a shape.

2. **Improve tool switching behavior**: Fixes issues with tool overlays not showing or being repeated when switching between tools. This includes:
   - Properly handling tool overlay visibility
   - Ensuring only one tool is active at a time when using keyboard shortcuts
   - Adding proper cleanup when switching tools

3. **Add comprehensive tests**: Adds new test cases to verify:
   - Shape creation with keyboard shortcuts
   - Shape text editing after mode switching
   - Tool switching behavior with keyboard shortcuts

blocksuite/affine/gfx/note/src/overlay/overlay.ts

@@ -26,7 +26,6 @@ export class NoteOverlay extends ToolOverlay {
 
   constructor(gfx: GfxController, background: Color) {
     super(gfx);
-    this.globalAlpha = 0;
     this.backgroundColor = gfx.std
       .get(ThemeProvider)
       .getColorValue(background, DefaultTheme.noteBackgrounColor, true);