fix: correctly check for promise in useLoadData

[NielsJPeschel]

Proposed changes

Currently, useLoadData makes the assumption a promise is a native promises. Non-native promises lead to a bug where we immediately assign loadedData.result a promise without ever evaluating that promise.

The fix is to go into further depth when checking initial promise.

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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Further comments

[NielsJPeschel]

@nthurow Ran this test with how useLoadData was written before (ie using instanceof Promise), and it did in fact fail! I was worried we wouldn't be able to test this scenario adequately, but glad that isn't the case!

[nthurow]

Excellent!

[NielsJPeschel]

we should start looking at automating this