Validate awsendpoint deletion

With current implementation the cpo private link controller will consider deletion successfull after making the request, however if the resource keeps existing somehow in AWS it would prevent the deletion of the awsendpointService resource by the HO AWSEndpointServiceReconciler with "failed to delete resource: Service has existing active VPC Endpoint connections!"
https://issues.redhat.com/browse/HOSTEDCP-597

control-plane-operator/controllers/awsprivatelink/awsprivatelink_controller.go

@@ -567,6 +567,27 @@ func (r *AWSEndpointServiceReconciler) delete(ctx context.Context, awsEndpointSe
 		}); err != nil {
 			return false, err
 		}
+
+		// check if Endpoint exists in AWS
+		output, err := ec2Client.DescribeVpcEndpointsWithContext(ctx, &ec2.DescribeVpcEndpointsInput{
+			VpcEndpointIds: []*string{aws.String(endpointID)},
+		})
+		if err != nil {
+			awsErr, ok := err.(awserr.Error)
+			if ok {
+				if awsErr.Code() != "InvalidVpcEndpointId.NotFound" {
+					return false, err
+				}
+			} else {
+				return false, err
+			}
+
+		}
+
+		if output != nil && len(output.VpcEndpoints) != 0 {
+			return false, fmt.Errorf("resource requested for deletion but still present")
+		}
+
 		log.Info("endpoint deleted", "endpointID", endpointID)
 	}