contexthub: close invalid session open requests

- Move halCloseEndpointSession(NoThrow) into ContextHubEndpointManager
- Call client side onCloseEndpointSession separately
- When there's a duplicated/invalid open request, call
  closeEndpointSession as needed

Test: ContextHubEndpointTest
Flag: EXEMPT, bug fix
Bug: 387716930
Change-Id: I802e09184608341186591188d15ec943b654269e