122464: Fixed a memory leak when initComponentInstance is called multiple times

(cherry picked from commit 62f15668b6)

src/app/shared/theme-support/themed.component.ts

@@ -82,6 +82,9 @@ export abstract class ThemedComponent<T> implements AfterViewInit, OnDestroy, On
   }
 
   initComponentInstance(changes?: SimpleChanges) {
+    if (hasValue(this.themeSub)) {
+      this.themeSub.unsubscribe();
+    }
     this.themeSub = this.themeService?.getThemeName$().subscribe(() => {
       this.renderComponentInstance(changes);
     });