MINOR: move r.Valid assignment after backendRef loop in HTTPRouteRule and TLSRouteRule

r.Valid = routeValid was inside the loop in the success branch only; failure
paths hit continue and skipped it, leaving r.Valid at its zero value (false).
The result was correct by coincidence but fragile. Moving the assignment after
the loop makes the intent explicit and safe against future refactors.

Author: ivanmatmati

k8s/gate/tree/route-rule.go

@@ -82,8 +82,8 @@ func (r *HTTPRouteRule) checkBackendRef(httpRoute *HTTPRoute, controllerStore Co
 			Valid:      true,
 			Conditions: rc.ConditionOKResolvedRef(),
 		})
-		r.Valid = routeValid
 	}
+	r.Valid = routeValid
 }
 
 // checkFilters validates the HTTPRoute filters at both rule and backendRef level.

k8s/gate/tree/tls-route-rule.go

@@ -78,8 +78,8 @@ func (r *TLSRouteRule) checkBackendRef(tlsRoute *TLSRoute, controllerStore Contr
 			Valid:      true,
 			Conditions: rc.ConditionOKResolvedRef(),
 		})
-		r.Valid = routeValid
 	}
+	r.Valid = routeValid
 }
 
 // ServiceNsNameKey returns the service Ns/Name