Allow conversion of QgsFeatureStoreList results to Python objects

[nyalldawson]

Fixes #39479

[agiudiceandrea]

Hi @nyalldawson I've tested the example provided in #39479 and now, with your fix, the error unable to convert a C++ 'QgsFeatureStoreList' instance to a Python object is gone. Thank you!

I noticed that in the classQgsRasterIdentifyResult API and PyQGIS docs, it's incorrectly reported that results() (for QgsRaster.IdentifyFormatFeature) returns a dictionary of "QgsRasterFeatureList for each sublayer".

Should it be QgsFeatureStoreList (which however is not documented anywhere) or something better (like "a list of QgsFeatureStore objects")?

This is what returns results() in Python:

>>> result.results()
{0: [<qgis._core.QgsFeatureStore object at 0x0000029E4748B678>]}
>>> type(result.results())
<class 'dict'>

>>> result.results()[0]
[<qgis._core.QgsFeatureStore object at 0x0000029E4748B5E8>]
>>> type(result.results()[0])
<class 'list'>

>>> result.results()[0][0]
<qgis._core.QgsFeatureStore object at 0x0000029E4748B708>
>>> type(result.results()[0][0])
<class 'qgis._core.QgsFeatureStore'>

[nyalldawson]

@agiudiceandrea fixed in #39605