Adopt ScreenshotPull task to support Gradle managed device

[olegosipenko]

Is your feature request related to a problem? Please describe. Currently when running screenshot tests on GMD we need to manually extract screenshots from the output directory inside build/outputs/managed_device_android_test_additional_output. It would be really nice if the screenshotPull task were able to understand when a GMD device is in-use and correctly copy the files from managed_device_android_test_additional_output automatically. This should be possible by checking the state of the useTestStorage flag in TestifySettings -- similar to how we check the SDCard flag.

This feedback relates to:

• [x] The Kotlin library
• [x] The Gradle plugin
• [ ] The IntelliJ Platform plugin
• [x] The sample code
• [x] The documentation

Describe the solution you'd like Check useTestStorage flag inside TestifySettings and pull screenshots from output folder.

[DanielJette]

https://github.com/ndtp/android-testify/issues/250#issuecomment-2681703733