chore(overlay): export ConnectedPosition interface (#10852)

* export ConnectedPosition with overlay public API

* Update public-api.ts

Author: jshoudy11

src/cdk/overlay/public-api.ts

@@ -24,5 +24,8 @@ export {OverlayPositionBuilder} from './position/overlay-position-builder';
 export {PositionStrategy} from './position/position-strategy';
 export {GlobalPositionStrategy} from './position/global-position-strategy';
 export {ConnectedPositionStrategy} from './position/connected-position-strategy';
-export {FlexibleConnectedPositionStrategy} from './position/flexible-connected-position-strategy';
+export {
+  ConnectedPosition,
+  FlexibleConnectedPositionStrategy,
+} from './position/flexible-connected-position-strategy';
 export {VIEWPORT_RULER_PROVIDER} from '@angular/cdk/scrolling';