fix(core): space inside menu input triggers ai menu (#12552)

> CLOSE AI-137

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

- **Bug Fixes**
  - Improved input field behavior in context menus by preventing unintended actions caused by keypress events.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/components/src/context-menu/input.ts

@@ -111,6 +111,7 @@ export class MenuInput extends MenuFocusable {
       }}"
       @input="${this.onInput}"
       placeholder="${this.data.placeholder ?? ''}"
+      @keypress="${this.stopPropagation}"
       @keydown="${this.onKeydown}"
       @copy="${this.stopPropagation}"
       @paste="${this.stopPropagation}"