sphinx_automodapi.automodsumm doesn't resolve autodoc_mock_imports

I have a python package module that imports 3rd party modules which aren't included in the sphinx documentation. So I added these modules to mock imports in the ``conf.py``

```python
autodoc_mock_imports = ["abaqus", "abaqusConstants","material","section","part","assembly", "step", "interaction","mesh","load","job","optimization","sketch", "odbAccess", "connectorBehavior","pandas","numpy","matplotlib","scipy"]
```

While using the mock imports works with the sphinx ``automodule`` directive without throwing an error.
```rst
.. automodule:: mymodule
```

I get the an error when using the module with ``automodapi`` directive.
```rst
.. automodapi:: mymodule
```
Error:
```
Extension error (sphinx_automodapi.automodsumm):
Handler for event 'builder-inited' threw an exception (exception: No module named 'abaqus')
```

Start with conf.py and compare how Sphinx's automodule handles autodoc_mock_imports with the automodapi directive. Trace sphinx_automodapi.automodsumm.process_automodsumm_generation; done means automodapi can document mymodule without raising No module named 'abaqus'.

Written by the indexing model from the issue text.