0f880e9200
## Description Before we deprecate the `RawKeyEvent` code, it needs to provide parity in functionality. One thing that is missing is the `eventSource` field from the `RawKeyEventDataAndroid` class, which provides the device type for the event. See https://developer.android.com/reference/android/view/InputDevice#SOURCE_KEYBOARD for an example. This PR implements that support, and sets the source to `KeyEventDeviceType.keyboard` for platforms that don't provide this information. The main thing it does is add the enum `KeyEventDeviceType`, and a new field `KeyData.deviceType`. ## Related Issues - https://github.com/flutter/flutter/issues/136419 ## Tests - Updated tests to also read/write/verify this property.