[MOD-2588] Android: Add fallback support to password, pin, or touch-pattern in "ti.identity"

*Summary:* The "ti.identity" module for Android should fallback to using the device's password, pin, or touch-pattern if a biometric means of identification (ie: touch id or face id) is not available. *To-Do:* When setting up the Java BiometricPrompt.PromptInfo.Builder, we should call the setDeviceCredentialAllowed() and to true to enable fallback support... but only https://developer.android.com/training/sign-in/biometric-auth#allow-fallback We should only set it to true if the module's AUTHENTICATION_POLICY_PASSCODE is set. This is for parity with iOS. Currently, we prompt in the following 2 places in the code... [FingerPrintHelper.java#L127](https://github.com/appcelerator-modules/titanium-identity/blob/3e0d849bf6e157df60b48efd272857fa4c3e8b4f/android/src/ti/identity/FingerPrintHelper.java#L127) [KeychainItemProxy.java#L159](https://github.com/appcelerator-modules/titanium-identity/blob/3e0d849bf6e157df60b48efd272857fa4c3e8b4f/android/src/ti/identity/KeychainItemProxy.java#L159)