fix: prevent error if getChildView is called with index out of bounds

Author: farfromrefug

src/ui-pager/index.android.ts

@@ -159,7 +159,7 @@ export class Pager extends PagerBase {
 
     getChildView(index: number): View {
         if (this._childrenViews) {
-            return this._childrenViews[index].view;
+            return this._childrenViews[index]?.view;
         }
         return this.enumerateViewHolders<View>((v) => (v.getAdapterPosition() === index ? v.view : undefined));
     }

src/ui-pager/index.common.ts

@@ -194,7 +194,7 @@ export abstract class PagerBase extends View implements AddChildFromBuilder {
     }
 
     getChildView(index: number): View {
-        return this._childrenViews && this._childrenViews[index].view;
+        return this._childrenViews && this._childrenViews[index]?.view;
     }
     _removeView(view: ViewBase) {
         // inside the recyclerview we wrap the PagerItem in a StackLayout

src/ui-pager/index.ios.ts

@@ -131,7 +131,7 @@ export class Pager extends PagerBase {
 
     getChildView(index: number): View {
         if (this._childrenViews) {
-            return this._childrenViews[index].view;
+            return this._childrenViews[index]?.view;
         }
         let result: View;
         if (this.nativeViewProtected) {