feat: [ACADEMIC-16209] Unit summary settings

[https://jira.2u.com/browse/ACADEMIC-16209](https://jira.2u.com/browse/ACADEMIC-16209)

1. Add unit xpert unit summaries settings behind flag `summaryhook_summaries_configuration` added [here](https://github.com/edx/ai-aside/pull/45/files)
2. Only show the checkbox when the value is a `boolean` otherwise the feature is considerer `disabled` by the flag.
3. Update block handler to update this value via `api` exposed [here](edx/ai-aside#43)
4. Create `AiAsideSummary` configuration class to provide access to the `ai_aside.api` endpoints.

cms/lib/test/test_ai_aside_summary_config.py

@@ -5,7 +5,7 @@
 
 import sys
 from unittest import TestCase
-from unittest.mock import Mock, patch
+from unittest.mock import Mock
 
 from opaque_keys.edx.keys import CourseKey, UsageKey