notebooks: support for copying
Created by: novoselrok
Fixes #30730 (closed)
Adds "Copy to My Notebooks" button next to "Run all blocks" and "Export to Markdown" buttons.
Test plan
- Create a notebook
- Click on the "Copy to My Notebooks" button
- You should be redirected to the newly copied notebook
- The notebook should be private
- I also added an integration test to cover this