Mobx dragdrop file fix

[nf-s]

Fix file drag and drop, and fix "auto" file type resolving

Fixes #4102

I have fixed drag and drop, and 'auto' file type resolving

Checklist

• Make auto file type work
• Discuss if we should refactor the whole CreateCatalogItemFromFileOrUrl... thing This can be discussed at a later stage
• Refactor if needed
• Add test for 'auto' file type
• I've updated CHANGES.md with what I changed.

[CLAassistant]

All committers have signed the CLA.

[na9da]

@nf-s Merging from the mobx branch should fix the CI errors.

[nf-s]

will do, thanks!

[rowanwins]

You've got prettier errors @nf-s so another update required :)

It turns out husky (which should auto-run prettier for you when you commit code) only works well with certain versions of node so you might need to just double check that.

[nf-s]

Drag dropping in CSVs now works.

Changes:

• Mobxified DragDropFile and DragDropNotification
• sourceReference not being passed through the CsvCatalogItem's constructor. A Developer error was being thrown but was not printed to console for some reason (and the error's stack trace was not useful).
• Change CsvCatalogItem's forceLoadTableData to load csvFiles before urls (I'm not sure of wider implications of doing this)
• Renamed createCatalogItemFromUrl to createUrlReferenceFromUrl to clear confusion between createCatalogItemFromUrl and createCatalogItemFromFileOrUrl
• After the UrlReference has been created in createCatalogItemFromFileOrUrl, the target is checked for hasFileInput (recursively)

The whole thing is a bit messy, but I'm not sure how to clean it up at this point:

• Maybe create a FileInputMixin or LocalDataMixin
• Or add some sort of fileInput to UrlReference
• The whole isUrl and allowLoad thing is confusing
• Should there be some separation of URL sources and file sources?

[nf-s]

I'm not sure why 1) changes cursor to crosshair when entering drawing mode - UserDrawing that requires WebGL test is failing

[nf-s]

Urgh - a test error:

should create an catalog item (CSVCatalogItem) from File (csv) without specifying a dataType
ReferenceError: 'fetch' is undefined

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