test: fix azure validation

Author: durran

src/cmap/auth/mongo_credentials.ts

@@ -182,9 +182,13 @@ export class MongoCredentials {
     }
 
     if (this.mechanism === AuthMechanism.MONGODB_OIDC) {
-      if (this.username && this.mechanismProperties.PROVIDER_NAME) {
+      if (
+        this.username &&
+        this.mechanismProperties.PROVIDER_NAME &&
+        this.mechanismProperties.PROVIDER_NAME !== 'azure'
+      ) {
         throw new MongoInvalidArgumentError(
-          `username and PROVIDER_NAME may not be used together for mechanism '${this.mechanism}'.`
+          `username and PROVIDER_NAME '${this.mechanismProperties.PROVIDER_NAME}' may not be used together for mechanism '${this.mechanism}'.`
         );
       }