bug: autofocus input causes modal animation be incorrect on ios

# Bug Report

**Ionic version:**

[x] **4.x**

**Current behavior:**

The same issue as reported in #16136:
When setting autofocus on an ion-input element in a modal in ios, the modal content disappears.

**Expected behavior:**

The modal content does not disappear.

**Steps to reproduce:**

1. Create an Ionic App
2. Create a Modal with `const modal = await this.modalController.create({...`
3. Set autofocus on an ion-input element in the modal component

**Related code:**

`modal.component.html`:
```

Some Modal Component

Some Input

```

**Other information:**

Related issue: #16136

**Ionic info:**

```
Ionic:

ionic (Ionic CLI) : 4.12.0
Ionic Framework : @ionic/angular 4.4.0
@angular-devkit/build-angular : 0.13.8
@angular-devkit/schematics : 7.3.8
@angular/cli : 7.3.8
@ionic/angular-toolkit : 1.5.1

Cordova:

cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
Cordova Platforms : android 7.1.4, ios 4.5.5
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 4.0.1, (and 4 other plugins)

System:

Android SDK Tools : 26.1.1
NodeJS : v11.9.0
npm : 6.9.0
OS : macOS Mojave
Xcode : Xcode 10.2.1 Build version 10E1001
```

Start with the modal.component.html reproduction and compare the behavior with related issue #16136. Reproduce the autofocus case on iOS, then trace the modal animation and ion-input interaction in the Ionic Framework source. Done means the modal content remains visible while the autofocus input is active.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.