fix(ThemeManager): Refactor ThemeManager class to separate global style setting logic

ts/domtools.classes.thememanager.ts

@@ -21,10 +21,13 @@ export class ThemeManager {
     this.updateAllConnectedElements();
   }
 
-  private async updateAllConnectedElements() {
+  private async setGlobalStylesOnPurpose() {
     if (document.body && document.body.style) {
       document.body.style.background = this.goBrightBoolean ? '#fff' : '#000';
     }
+  }
+
+  private async updateAllConnectedElements() {
     this.themeObservable.next(this.goBrightBoolean);
   }