bug: modal animation needs to account for viewport resizing when dismissing keyboard and modal

# Bug Report

**Ionic version:**
[x] **5.x**

**Current behavior:**
Issue originally reported here: [#20686](https://github.com/ionic-team/ionic-framework/issues/20686). Still seeing this on the latest version of Ionic Framework.

**Expected behavior:**
When dismissing a modal while the keyboard is open, the close animation should not be affected by the keyboard

**Steps to reproduce:**
Sample App here: https://github.com/cesaresantiago/keyboard-modal-dismiss-glitch

Run this code on an iOS device/simulator. Closing the modal by itself works fine, however, if the the keyboard is open the modal close animation closes to the height of the keyboard before snapping away the final 30% of the screen.

**Related code:**

**Ionic info:**

```
Ionic:
Ionic CLI : 6.11.0 (/Users/dallas/.nvm/versions/node/v14.6.0/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/angular 5.3.2
@angular-devkit/build-angular : 0.1000.8
@angular-devkit/schematics : 10.0.8
@angular/cli : 10.0.8
@ionic/angular-toolkit : 2.3.3
Cordova:
Cordova CLI : 9.0.3 (cordova-lib@9.0.2)
Cordova Platforms : ios 5.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 4.2.1, (and 4 other plugins)
Utility:
cordova-res : 0.15.1
native-run : 1.0.0
System:
ios-sim : 8.0.2
NodeJS : v14.6.0 (/Users/dallas/.nvm/versions/node/v14.6.0/bin/node)
npm : 6.14.7
OS : macOS Catalina
Xcode : Xcode 11.6 Build version 11E708
```