UI: Fix compilation error after merge.

ui-ngx/src/app/modules/home/components/widget/lib/settings/common/scada/scada-symbol-object-settings.component.ts

@@ -21,7 +21,6 @@ import {
   forwardRef,
   Input,
   OnChanges,
-  OnDestroy,
   OnInit,
   SimpleChanges
 } from '@angular/core';
@@ -73,7 +72,7 @@ import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
     }
   ]
 })
-export class ScadaSymbolObjectSettingsComponent implements OnInit, OnChanges, ControlValueAccessor, Validator, OnDestroy {
+export class ScadaSymbolObjectSettingsComponent implements OnInit, OnChanges, ControlValueAccessor, Validator {
 
   ScadaSymbolBehaviorType = ScadaSymbolBehaviorType;
 
@@ -141,13 +140,6 @@ export class ScadaSymbolObjectSettingsComponent implements OnInit, OnChanges, Co
     }
   }
 
-  ngOnDestroy() {
-    if (this.validatorSubscription) {
-      this.validatorSubscription.unsubscribe();
-      this.validatorSubscription = null;
-    }
-  }
-
   registerOnChange(fn: any): void {
     this.propagateChange = fn;
   }