feat(ui): canvas auto mask followups 3

[psychedelicious]

Summary

• Fix issue where right-clicking the canvas w/ eraser tool would erase and then open the menu.
• Add help tooltip to Auto-mask explaining how to use the feature.
  
• Disable copy to clipboard when a layer is empty
• Support image dnd for Inpaint Mask and Regional Guidance
  • New canvas drop targets for New Inpaint Mask and New Regional Guidance
    
  • New Replace Layer drop targets for Inpaint Mask and Regional Guidance
    
• Fix issue w/ no cursor during transform when brush tool selected

Related Issues / Discussions

offline discussion

QA Instructions

try the things out

Merge Plan

n/a

Checklist

• The PR has a short but descriptive title, suitable for a changelog
• Tests added / updated (if applicable)
• Documentation added / updated (if applicable)

[psychedelicious]

• Reverted inpaint mask and regional guidance drop targets - determined these are confusing
• Added New from Image sub-menu to image ctx menu