[video] Allow changing the type of a movie asset between version and extra

[CrystalP]

Description

There was no reason to prevent the change of a movie version into an extra of the same movie (or vice versa).

That type of change is done through the "Add" button of the Versions/Extras Manger dialog and was already allowed and working when turning a movie version into an extra of a different movie for example.

The PR fine-tunes a couple conditions when adding a file as version or extra to a movie:

• Same movie and same asset type (adding a version and asset was a version): rejected - should use the rename function instead

• Same movie and different asset type (adding a version and the asset was an extra, or adding an extra and the asset was a version): allowed

• The confirmation popup about moving an asset to a different movie only shows when actually moving an asset to a different movie. Was showing in other cases as well before PR.

Motivation and context

Reported by patk in Slack.

How has this been tested?

Changed movie version into extra of same movie, changed movie extra into version of same movie.

What is the effect on users?

Remove surprising behavior of versions/extras manager add buttons.

Screenshots (if appropriate):

Before:

After:

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• Student submission (PR was done for educational purposes and will be treated as such)
• None of the above (please explain below)

Checklist:

• My code follows the Code Guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the Contributing document
• I have added tests to cover my change
• All new and existing tests passed

[CrystalP]

Jenkins build this please

[ksooo]

LGTM