add exports to reduce duplication

Signed-off-by: Karl Haworth <karl.haworth@aa.com>

plugins/apollo-explorer/src/components/ApolloExplorerPage/index.ts

@@ -14,3 +14,4 @@
  * limitations under the License.
  */
 export { ApolloExplorerPage } from './ApolloExplorerPage';
+export type { EndpointProps } from './components/ApolloExplorerPage';

plugins/apollo-explorer/src/index.ts

@@ -20,3 +20,4 @@
  * @packageDocumentation
  */
 export { apolloExplorerPlugin, ApolloExplorerPage } from './plugin';
+export type { EndpointProps } from './ApolloExplorerPage';