refactor: clean up retrieval from data transfer item

[jonkoops]

What kind of change does this PR introduce?

• Bug Fix
• Feature
• Refactoring
• Style
• Build
• Chore
• Documentation
• CI

Did you add tests for your changes?

• Yes, my code is well tested
• Not relevant

If relevant, did you update the documentation?

• Yes, I've updated the documentation
• Not relevant

Summary
Cleans up the code in the fromDataTransferItem() function so that it is fully type-safe and uses await everywhere for Promises.

Does this PR introduce a breaking change?
No

Other information
Not relevant

[coveralls]

Pull Request Test Coverage Report for Build 12183872816

Details

• 16 of 16 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 12068096439:	0.0%
Covered Lines:	96
Relevant Lines:	96

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💛 - Coveralls

[jonkoops]

This PR builds off the work from #112, so that should be merged first so this can be rebased on top.

[jonkoops]

Re-based the PR and cleaned it up a little, I think we're good to go like this. @rolandjitsu can I ask you for a review?

[jonkoops]

I'll put this PR on hold until we merged the backport under #122, as this is likely to create conflicts.

[jonkoops]

@rolandjitsu I've rebased this PR on top of the fixes we backported from master, could I ask you for another pass?

Since the backports included converting the method to use await that enhancement no longer applies here, but the changes still include some additional type-safety fixes and improves the error messages, along with splitting up some of the code a bit more, so I think it is still relevant to land this.

[jonkoops]

As for the advanced errors with details about the handle, I think we could handle (no pun intended) that as a separate feature. Since the original error messages are kinda broken, and I have not seen anyone complain about it I think we can safely assume it is not that important to users, or they just don't get these messages often (or at all).

[jonkoops]

@rolandjitsu did another pass and processed your comments, could I ask you for another review?

[rolandjitsu]

@rolandjitsu did another pass and processed your comments, could I ask you for another review?

Sorry for the long wait. Got a bit busy at work.

[jonkoops]

No worries, I know how it is :)