Add settings modal for Xpert Learning Assistant feature. (#794)

* feat: modify AppSettingsModal to add bodyChildren prop and to make the learnMoreText prop optional

This commit adds a new bodyChildren prop to the AppSettingsModal component. This prop is meant to be used by a parent to pass through React components that should be rendered between the enable toggle and the form. This allows parents to specify additional UI that doesn't belong in the form. For example, additional documentation about the feature or additional links are examples of additional UI that can be rendered this way.

This commit modifies the learnMoreText prop to the AppSettingsModal component optional. The learnMoreText prop is used as the text for the "learn more configuration" link. This link is rendered only if the corresponding documentationLink is provided, and this link is optional. Therefore, the corresponding learnMoreText prop should also be optional.

* feat: modify PagesAndResources to support additional pages in the "content permissions" section

This commit modifies the way that the PagesAndResources component renders pages in the "content permissions" section to enable additional pages in this section beyond just the Xpert unit summaries feature.

* feat: add settings modal for Xpert Learning Assistant feature

This commit adds a settings modal for the Xpert Learning Assistant feature.

jest.config.js

@@ -15,4 +15,7 @@ module.exports = createConfig('jest', {
   moduleNameMapper: {
     '^lodash-es$': 'lodash',
   },
+  modulePathIgnorePatterns: [
+    '/src/pages-and-resources/utils.test.jsx',
+  ],
 });