Problem description
Commonalities has removed the IDENTIFIER_MISMATCH error for Fall25

Expected behaviour

• 422 IDENTIFIER_MISMATCH must not be a possible error response.
• When device disambiguation is required, add a device property of type DeviceResponse to the response to indicate which device identifier is being used by the implementation
• Update test cases and documentation

Alternative solution
None

Additional context
This change only affects implementations that accept 2-legged access tokens