Migrate amazon provider operator tests from unittests to pytest

[IAL32]

Related: #28039 #28139 #28145 @Taragolis

Migrate Amazon provider's transfer tests to pytest.

All changes are more or less straightforward:

• Get rid of unittests.TestCase class and TestCase.assert* methods
• Convert setUp* and tearDown* methods to appropriate pytest alternative
• Replace decorator parameterized.expand by pytest.mark.parametrize.
• Renamed @patch to @mock.patch to conform to other tests

[IAL32]

Note: previous implementation relied on the fact that executing the operator actively modified the CREATE_TRANSFORM_PARAMS constant, which is bad practice. Here I provide a second dictionary with the expected integer values and modified tests accordingly.

[IAL32]

@Taragolis all done!