Add get_catalog_for_single_relation to MockAdapter

[aranke]

Example failing logs:

        mock_mp_context = mock.MagicMock()
        adapter_class = adapter_factory()
>       return adapter_class(mock_config, mock_mp_context)
E       TypeError: Can't instantiate abstract class MockAdapter with abstract method get_catalog_for_single_relation

tests/unit/context/test_context.py:157: TypeError

---------- coverage: platform linux, python 3.11.9-final-0 -----------
Coverage XML written to file coverage.xml

=========================== short test summary info ============================
ERROR tests/unit/context/test_context.py::TestParseWrapper::test_unwrapped_method
ERROR tests/unit/context/test_context.py::TestParseWrapper::test_wrapped_method
ERROR tests/unit/context/test_context.py::TestRuntimeWrapper::test_unwrapped_method

Similar fix in dbt-snowflake: https://github.com/dbt-labs/dbt-snowflake/pull/1064/files#diff-89d74eae44795c1174908ac6de68178b1c8c27db47d7531a4533b72b42963856R36-R38

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.79%. Comparing base (0fdc83a) to head (d964e52).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10336      +/-   ##
==========================================
+ Coverage   86.08%   88.79%   +2.70%     
==========================================
  Files         180      180              
  Lines       22490    22490              
==========================================
+ Hits        19361    19969     +608     
+ Misses       3129     2521     -608     

Flag	Coverage Δ
integration	86.08% <ø> (ø)
unit	62.19% <ø> (?)

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