Add _MockPropertyFieldsContainer class #3897

Job	Run time
Style Check	54s
debug	2s
tests / Setup	1s
retro 232 / Setup	1s
Build and Test on Docker / Build and Test On Docker (3.8, ubuntu-latest)	25m 46s
Run examples on Docker / Setup	1s
retro 231 / Setup	1s
examples / Setup	1s
docs / Documentation	33m 40s
PyDPF-Post / Clone and Test (windows-latest, 3.8)	9m 38s
PyDPF-Post / Clone and Test (ubuntu-latest, 3.8)	7m 28s
retro 221 / Setup	1s
retro 222 / Setup	1s
docs / Check doc style / Documentation Style Check	57s
tests / Tests (3.8, windows-latest)	27m 34s
tests / Tests (3.8, ubuntu-latest)	17m 41s
retro 232 / Tests (3.8, windows-latest)	17m 49s
retro 232 / Tests (3.8, ubuntu-latest)	14m 1s
Run examples on Docker / Run Examples (3.8, ubuntu-latest)	19m 13s
examples / Run Examples (3.8, windows-latest)	14m 26s
examples / Run Examples (3.8, ubuntu-latest)	10m 48s
retro 222 / Tests (3.8, windows-latest)	10m 12s
retro 222 / Tests (3.8, ubuntu-latest)	7m 12s
retro 231 / Tests (3.8, windows-latest)	16m 43s
retro 231 / Tests (3.8, ubuntu-latest)	10m 15s
retro 221 / Tests (3.8, windows-latest)	9m 55s
retro 221 / Tests (3.8, ubuntu-latest)	13m 53s
upload-development-docs	0s
	4h 28m 14s

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