[PROD-3727] [FIX] refactoring

ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-service-rpc-connector.component.ts

@@ -143,12 +143,7 @@ export class GatewayServiceRPCConnectorComponent implements OnInit, OnDestroy, C
       }
     });
     this.isMQTTWithResponse = this.fb.control(false);
-    this.isMQTTWithResponse.valueChanges.pipe(
+    this.observeMQTTWithResponse();
-      tap(() => {
-        this.commandForm.get('responseTopicExpression').updateValueAndValidity();
-      }),
-      takeUntil(this.destroy$),
-    ).subscribe();
   }
 
   ngOnDestroy(): void {
@@ -452,4 +447,13 @@ export class GatewayServiceRPCConnectorComponent implements OnInit, OnDestroy, C
       return null;
     };
   }
+
+  private observeMQTTWithResponse(): void {
+    this.isMQTTWithResponse.valueChanges.pipe(
+      tap(() => {
+        this.commandForm.get('responseTopicExpression').updateValueAndValidity();
+      }),
+      takeUntil(this.destroy$),
+    ).subscribe();
+  }
 }