refactor: Remove unused CreateLegacyLibraryModal

The CreateLegacyLibrary page is used, but the Modal version
isn't. Remove to avoid adding dead code and decreasing test
coverage. I added it in the first place to replicate
CreateLibraryModal (which doesn't seem to be used either).

Author: kdmccormick

src/library-authoring/create-legacy-library/CreateLegacyLibraryModal.tsx

@@ -1,2 +1 @@
 export { CreateLegacyLibrary } from './CreateLegacyLibrary';
-export { CreateLegacyLibraryModal } from './CreateLegacyLibraryModal';

src/library-authoring/create-legacy-library/index.ts

@@ -2,6 +2,6 @@ export { default as LibraryLayout } from './LibraryLayout';
 export { ComponentPicker } from './component-picker';
 export { type SelectedComponent } from './common/context/ComponentPickerContext';
 export { CreateLibrary, CreateLibraryModal } from './create-library';
-export { CreateLegacyLibrary, CreateLegacyLibraryModal } from './create-legacy-library';
+export { CreateLegacyLibrary } from './create-legacy-library';
 export { libraryAuthoringQueryKeys, useContentLibraryV2List } from './data/apiHooks';
 export { default as PreviewChangesEmbed } from './legacy-integration/PreviewChangesEmbed';