[SL-UP] Add an implementation of GetOtaTlvEncryptionKeyId

Author: chirag-silabs

examples/platform/silabs/tests/TestSilabsTestEventTrigger.cpp

@@ -56,6 +56,10 @@ class ProviderStub : public ProvisionedDataProvider
 
     void SetForceError(bool value) { forceError = value; }
 
+    CHIP_ERROR GetOtaTlvEncryptionKeyId(uint32_t & value) override {
+        value = 0;
+        return CHIP_NO_ERROR;
+    }
 private:
     uint8_t mEnableKey[TestEventTriggerDelegate::kEnableKeyLength] = { 0 };
     bool forceError                                                = false;