Splash screen not accepted by iOS14+ because of its size

Make generated assets to comply with iOS spec. According to Apple doc [responding-to-the-launch-of-your-app](https://developer.apple.com/documentation/uikit/responding-to-the-launch-of-your-app) splash screen size must not exceed 25MB for iOS 14+. It seems to be size of raw bitmap _width x height x 4 bytes_. Which makes images of size 2732 x 2732 too big and not accepted by device. There is no way to instruct _capacitor-assets_ tool to generate splash screen images with smaller resolution in _ios/App/App/Assets.xcassets/Splash.imageset_.

See snapshot from device log with iOS 16:

Jul 30 11:31:26 splashboardd[423] : Error generating launch image for de.usu.smartlink1:
Jul 30 11:31:26 splashboardd[423] : [] launch image generation failed with error: Error Domain=XBLaunchStoryboardErrorDomain Code=6 "Unable to generate launch image" UserInfo={XBApplicationBundleIdentifier=, NSLocalizedDescription=Unable to generate launch image, NSLocalizedFailureReason=}
Jul 30 11:31:26 splashboardd[423] : XBLaunchImageProviderServer encountered an error with code: 6 during launch image generation for bundleID: de.usu.smartlink1
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Error generating image for launch request .
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Snapshot generation resulted in an error with code: 6 for app bundleID:
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Noting that the application has a bad launch image until it is updated.
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Skipping launch request due to denied app: .
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Skipping launch request due to denied app: .
Jul 30 11:31:26 SpringBoard(SplashBoard)[34] : Skipping launch request due to denied app: .
Jul 30 11:31:27 SpringBoard(SplashBoard)[34] : Snapshot generation request for bundleID: de.usu.smartlink1 rejected due to the app being denylisted.