paddingBottom param is not working properly under iOS

[ryaa]

Describe the bug
paddingBottom param is not working properly on iOS - see this param desc https://github.com/ryaa/camera-preview/tree/master#startoptions

To Reproduce
Steps to reproduce the behaviour:

1. make sure that the device is in portrait or landscape orientation
2. start a camera with toBack set to false (or does not set it so that the default value is used) and paddingBottom param set in CameraPreviewOptions on iOS
   Note that the padding is not applied
3. rotate the device
   Note that the padding is not applied

Note that padding bottom is not applied and the preview takes the entire screen. This commit broke the padding after rotation - see af469a5

See my comment here af469a5#r50558659
Before it used to calculate height but after the change it uses the original height without bottom padding.

Expected behavior
The param must works as advertised in the plugin README

Screenshots

Desktop (please complete the following information):

• OS: MacOS Big Sur 11.2.3

Smartphone (please complete the following information):

• Device: IPhone 6S Plus
• OS: iOS 14.5

Additional context
N/A