fix(mobile): incorrect height of keyboard toolbar in ios (#8653)

### What Changes:
- Fix keyboard height calculation with the `KeyboardToolBarConfig.useScreenHeight = true`. More detials in: https://github.com/toeverything/blocksuite/pull/8645
- Add safe bottom padding for shrinked keyboard toolbar
- Add `VirtualKeyboard` polyfill. Close [AF-1573](https://linear.app/affine-design/issue/AF-1573/virtualkeyboard-polyfill-with-capacitor)
  - Since the `@capacitor/keyboard` dose not implement the `Keyboard.show()` method, this polyfill is not enabled now.

packages/frontend/apps/ios/App/Podfile

@@ -13,6 +13,7 @@ def capacitor_pods
   pod 'CapacitorCordova', :path => '../../../../../node_modules/@capacitor/ios'
   pod 'CapacitorApp', :path => '../../../../../node_modules/@capacitor/app'
   pod 'CapacitorBrowser', :path => '../../../../../node_modules/@capacitor/browser'
+  pod 'CapacitorKeyboard', :path => '../../../../../node_modules/@capacitor/keyboard'
 end
 
 target 'App' do