Remove unused IdentityConstants import from DefaultAzureCredentialBuilder

Co-authored-by: srnagar <[email protected]>

Author: Copilot

sdk/identity/azure-identity/src/main/java/com/azure/identity/DefaultAzureCredentialBuilder.java

@@ -8,7 +8,6 @@
 import com.azure.core.util.CoreUtils;
 import com.azure.core.util.logging.ClientLogger;
 import com.azure.identity.implementation.IdentityLogOptionsImpl;
-import com.azure.identity.implementation.util.IdentityConstants;
 import com.azure.identity.implementation.util.IdentityUtil;
 
 import java.time.Duration;