[MM-64358] don't save unneeded custom profile attributes (#8971)

* send only needed changes, take saml into account

* adhere to naming conventions

* fix tests

* address review comments

types/api/custom_profile_attributes.d.ts

@@ -22,6 +22,7 @@ type CustomProfileField = {
     /** any extra properties of the field **/
     attrs?: {
         sort_order?: number;
+        saml?: string;
         [key: string]: unknown;
     };