Add a way ask a DeviceCommissioner for its DeviceAttestationVerifier. (#28587)

diff --git a/src/controller/CHIPDeviceController.h b/src/controller/CHIPDeviceController.h
index 2d85fdc..b328ef6 100644
--- a/src/controller/CHIPDeviceController.h
+++ b/src/controller/CHIPDeviceController.h
@@ -702,6 +702,8 @@
         mDeviceAttestationVerifier = deviceAttestationVerifier;
     }
 
+    Credentials::DeviceAttestationVerifier * GetDeviceAttestationVerifier() const { return mDeviceAttestationVerifier; }
+
     Optional<CommissioningParameters> GetCommissioningParameters()
     {
         return mDefaultCommissioner == nullptr ? NullOptional : MakeOptional(mDefaultCommissioner->GetCommissioningParameters());