fix aml workspace schema types mismatch for show operation (Azure#27269)

* Update changelog

* fix workspace.identity.UAI types mismatch for show operation

* revert the change log

* fix pylint issue

Co-authored-by: Diondra Peck <16376603+diondrapeck@users.noreply.github.com>
Co-authored-by: Mingwei He <mingweihe@microsoft.com>

sdk/ml/azure-ai-ml/azure/ai/ml/_schema/workspace/identity.py

@@ -5,7 +5,7 @@
 # pylint: disable=unused-argument,no-self-use
 
 from marshmallow import fields
-from marshmallow.decorators import post_load
+from marshmallow.decorators import post_load, pre_dump
 
 from azure.ai.ml._schema.core.fields import NestedField, StringTransformedEnum
 from azure.ai.ml._schema.core.schema_meta import PatchedSchemaMeta
@@ -40,6 +40,12 @@ class IdentitySchema(metaclass=PatchedSchemaMeta):
         keys=fields.Str(required=True), values=NestedField(UserAssignedIdentitySchema, allow_none=True), allow_none=True
     )
 
+    @pre_dump
+    def predump(self, data, **kwargs):
+        if data and isinstance(data, IdentityConfiguration):
+            data.user_assigned_identities = self.uai_list2dict(data.user_assigned_identities)
+        return data
+
     @post_load
     def make(self, data, **kwargs):
         data["user_assigned_identities"] = self.uai_dict2list(data.pop("user_assigned_identities"))
@@ -55,3 +61,17 @@ def uai_dict2list(self, uai_dict):
             p_id = meta.principal_id
             res.append(ManagedIdentityConfiguration(resource_id=resource_id, client_id=c_id, principal_id=p_id))
         return res
+
+    def uai_list2dict(self, uai_list):
+        res = {}
+        if uai_list and isinstance(uai_list, list):
+            for uai in uai_list:
+                if not isinstance(uai, ManagedIdentityConfiguration):
+                    continue
+                meta = {}
+                if uai.client_id:
+                    meta["client_id"] = uai.client_id
+                if uai.principal_id:
+                    meta["principal_id"] = uai.principal_id
+                res[uai.resource_id] = meta
+        return res if res else None