Expose DevSettingsActivity only in Debug build

[emanuelb]

The DevSettingsActivity activity is exposed on all releases, as it's declared in main folder at:

BitcoinWalletMobile/android/app/src/main/AndroidManifest.xml

Line 33 in 893175f

<activity android:name="com.facebook.react.devsupport.DevSettingsActivity" />

From react documentation at "Android (Java)" > "Configuring permissions":
https://reactnative.dev/docs/integration-with-existing-apps#configuring-permissions

If you need to access to the DevSettingsActivity add to your AndroidManifest.xml:

This is only used in dev mode when reloading JavaScript from the development server, so you can strip this in release builds if you need to.

The source code of "DevSettingsActivity.java" contain comment about this issue:

https://github.com/facebook/react-native/blob/3b31e69e284074da72108edfb11e41ee74d7100e/ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSettingsActivity.java#L14-L17

/**
 * Activity that display developers settings. Should be added to the debug manifest of the app. Can
 * be triggered through the developers option menu displayed by {@link DevSupportManager}.
 */

Fix: Declare DevSettingsActivity activity in ./android/app/src/debug/AndroidManifest.xml instead.