fix: make ChangeDetectorRef a required dependency

Author: Akshat55

src/popover/popover.directive.ts

@@ -96,11 +96,7 @@ export class PopoverContainer {
 		"left" | "left-bottom" | "left-top" |
 		"right" | "right-bottom" | "right-top" = "bottom";
 
-	private changeDetectorRef: ChangeDetectorRef;
-
-	constructor(ref?: ChangeDetectorRef) {
-		this.changeDetectorRef = ref;
-	}
+	constructor(private changeDetectorRef: ChangeDetectorRef) {}
 
 	handleChange(open: boolean, event: Event) {
 		if (this.isOpen !== open) {
@@ -113,6 +109,6 @@ export class PopoverContainer {
 			this.onClose.emit(event);
 		}
 		this.isOpen = open;
-		this.changeDetectorRef?.markForCheck();
+		this.changeDetectorRef.markForCheck();
 	}
 }