iOs banner makes the area behind untouchable if "No ad"

**Describe the bug**
In Russia Google does not load ad, but in different russian speaken countries ad is loaded correctly. In Russia because of Google send "No ad" response the area behind banner become untouchable. It means that banner height is not set and area uses for app logic. For example, at the bottom of the screen there is a "Settings" button that cannot be clicked due to a strange bug. From time to time.

Perhaps Google send some response and after that admob plugin logic set height is 0 but is starting to prepare area for ad that will never be loaded.

**To Reproduce**
Steps to reproduce the behavior:
1. Use VPN to Russia
2. Open app with banner
3. Find a button at bottom of screen
4. Check that it's not clickable (try to close app if it works and open again, try to use another app functions - bug appears suddenly)

**Expected behavior**
Area should be clickable

**Additional context**
Plugin version 4.1.0 ios

Start by reproducing the banner issue in an app with a bottom Settings button while using a Russia VPN and iOS plugin version 4.1.0. Inspect the iOS banner handling around the “No ad” response; done means the area behind an unloaded banner remains clickable and the behavior is reliable across app restarts.

Written by the indexing model from the issue text.