[Multiple Datasource] Export DataSourcePluginRequestContext at top le…

…vel for plugins to use (#6108) (#6111)

* export context as top level

Signed-off-by: Lu Yu <nluyu@amazon.com>

* add changelog

Signed-off-by: Lu Yu <nluyu@amazon.com>

---------

Signed-off-by: Lu Yu <nluyu@amazon.com>
(cherry picked from commit ead2947)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

# Conflicts:
#	CHANGELOG.md

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

src/plugins/data_source/server/index.ts

@@ -20,4 +20,8 @@ export function plugin(initializerContext: PluginInitializerContext) {
   return new DataSourcePlugin(initializerContext);
 }
 
-export { DataSourcePluginSetup, DataSourcePluginStart } from './types';
+export {
+  DataSourcePluginSetup,
+  DataSourcePluginStart,
+  DataSourcePluginRequestContext,
+} from './types';