refactor: update TextMenu and Variable nodes to ensure copy action wo…

[patelajay745]

#277 Solved this copying issue.

Now it will open fallback popup on double click.

Please check Video for reference.

https://github.com/user-attachments/assets/839d5cb6-b05f-4550-acb4-9a01a89e03d5

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Summary by cubic

Refactored the email editor’s TextMenu and Variable node behavior to fix the copy/select issue so users can reliably select and copy text and variables. Addresses issue #277.

• Bug Fixes
  • Simplified BubbleMenu show logic with stricter checks to prevent it from appearing during quick selections.
  • Kept BubbleMenu hidden on non-text nodes (image, logo, spacer, variable, link, button) to avoid interfering with copy.
  • Variable popover now opens on double-click, uses local isEditing, and closes cleanly when dismissed, so single-click selection/copy works as expected.

^{Written for commit 1f9274f99488f1575b9568e581a696a6019e2816. Summary will update automatically on new commits.}

Summary by CodeRabbit

• New Features

  • Variable editing: double-click variables to open an inline popover for editing fallback values; submit to close the editor.

• Improvements

  • Text formatting menu: minor UI/style consistency tweaks (no change to existing controls or behavior).