Clarify using commas in connection strings (#217)

* update details for connection strings

* specify property

* implement feedback

Author: stephmarie17

source/fundamentals/enterprise-authentication.txt

@@ -297,6 +297,10 @@ see the corresponding syntax.
       The following code example shows how to specify Azure IMDS OIDC authentication. 
       Replace the ``<percent-encoded audience>`` placeholder with the percent-encoded
       value of the ``audience`` parameter configured on your MongoDB deployment. 
+
+      You cannot pass values containing the comma (``,``) character to the ``authMechanismProperties`` 
+      option. You must specify values that contain commas in a ``MongoCredential`` object, 
+      as demonstrated in the :guilabel:`MongoCredential` tab.
 
       .. code-block:: csharp
 
@@ -346,7 +350,11 @@ see the corresponding syntax.
       The following code example shows how to specify GCP IMDS OIDC authentication as
       part of the authentication string. 
       Replace the ``<audience>`` placeholder with the
-      value of the ``audience`` parameter configured on your MongoDB deployment. 
+      value of the ``audience`` parameter configured on your MongoDB deployment.
+
+      You cannot pass values containing the comma (``,``) character to the ``authMechanismProperties`` 
+      option. You must specify values that contain commas in a ``MongoCredential`` object, 
+      as demonstrated in the :guilabel:`MongoCredential` tab.
 
       .. code-block:: csharp