[FR] Data import from local to Cloud is unintuitive

### Description

I decided to use AppFlowy Cloud Beta with my Github account, and wanted to import my old local data to my cloud, but it was very unintuitive since I had to find which directory to import. Displaying a popup after connection asking if you want to import your local data to the logged in cloud account would be a good UX enhancement imho.

### Impact

All users can benefit this enhancement.

### Additional Context

_No response_