[CosmosDB] Changing the warning message for AnalyticalStorageSchemaType (Azure#15723)

* changing the warning message for AnalyticalStorageSchemaType to only display when a value has been explicitly provided

* adjusting the changelog

* Update changelog

Co-authored-by: Yeming Liu <[email protected]>

Author: toswedlu

src/CosmosDB/CosmosDB/ChangeLog.md

@@ -19,6 +19,7 @@
 -->
 
 ## Upcoming Release
+* Fixed when a warning about the value of AnalyticalStorageSchemaType is displayed when no value was given.
 
 ## Version 1.4.0
 * Introduced Get-AzCosmosDBMongoDBBackupInformation to retrieve latest backup information for MongoDB.

src/CosmosDB/CosmosDB/CosmosDBAccount/NewOrUpdateAzCosmosDBAccount.cs

@@ -170,8 +170,11 @@ protected AnalyticalStorageConfiguration CreateAnalyticalStorageConfiguration(st
                     break;
 
                 default:
-                    string message = $"Invalid value for AnalyticalStorageSchemaType.  Valid values are '{SDKModel.AnalyticalStorageSchemaType.WellDefined}' and '{SDKModel.AnalyticalStorageSchemaType.FullFidelity}'.";
-                    WriteWarning(message);
+                    if (!string.IsNullOrWhiteSpace(param))
+                    {
+                        string message = $"Invalid value for AnalyticalStorageSchemaType.  Valid values are '{SDKModel.AnalyticalStorageSchemaType.WellDefined}' and '{SDKModel.AnalyticalStorageSchemaType.FullFidelity}'.";
+                        WriteWarning(message);
+                    }
                     break;
             }
             return retval;