[MM-52979]: Remove code around abandoned MUI modal migration (#23556)

webapp/channels/src/components/cloud_start_trial/request_business_email_modal.test.tsx

@@ -10,7 +10,7 @@ import {shallow} from 'enzyme';
 
 import * as cloudActions from 'actions/cloud';
 
-import GenericModal from 'components/generic_modal';
+import {GenericModal} from '@mattermost/components';
 
 import {mountWithIntl} from 'tests/helpers/intl-test-helper';
 import mockStore from 'tests/test_store';

webapp/channels/src/components/cloud_start_trial/request_business_email_modal.tsx

@@ -16,7 +16,7 @@ import {validateBusinessEmail} from 'actions/cloud';
 
 import {ItemStatus, TELEMETRY_CATEGORIES, ModalIdentifiers, LicenseLinks, AboutLinks} from 'utils/constants';
 
-import GenericModal from 'components/generic_modal';
+import {GenericModal} from '@mattermost/components';
 import {CustomMessageInputType} from 'components/widgets/inputs/input/input';
 import ExternalLink from 'components/external_link';