WKWebView is not resized properly after the native keyboard closes

## Bug Report

### Plugin(s)
@capacitor/keyboard 6.0.2

### Capacitor Version
@capacitor/cli: 6.1.2
@capacitor/core: 6.1.2
@capacitor/android: 6.1.2
@capacitor/ios: 6.1.2

### Platform(s)
ios & android

### Current Behavior
Occasionally, when the keyboard closes, the webview doesn't resize. Instead it leaves a massive empty black space where the keyboard was. Even on subsequent opens & closes of the keyboard, the webivew then never resizes.

### Expected Behavior
The webview should always resize to fill this space when the keyboard closed.

### Code Reproduction
Unfortunately this issue is very hard to reproduce. I see it maybe once a week. The only pattern I've identified so far is that it seems to happen in low power mode on my iphone.

### Additional Context
I've seen this issue appear on several devices, and there seems to be at least one other ticket open on webview resizing issues (https://github.com/ionic-team/capacitor-keyboard/issues/12).