Artboard duplication optimizations

Fixes and improvements

• Fixed copy-pasting keys issue introduced in 0.8.756.

• Optimized artboard duplication to significantly reduce the duplication time with complex artboards and avoid “locking up” the editor.

• Added “Loading…” status to the Revision History UI to prevent clicking the “Restore” button before the selected revision is loaded.

• Resolved Windows desktop app crash when using keyboard arrow keys to edit zoom level when Wacom drivers are installed.

• [Website] Restored Delete Account option in Account.

• [Website] Fixed Upload Avatar feature in Account.