[AC-1786] deprecate manager role (#6931)

* add deprecation message

* hide manager option

* deprecate manager enum

libs/common/src/admin-console/enums/organization-user-type.enum.ts

@@ -2,6 +2,10 @@ export enum OrganizationUserType {
   Owner = 0,
   Admin = 1,
   User = 2,
+  /**
+   * @deprecated
+   * This is deprecated with the introduction of Flexible Collections.
+   */
   Manager = 3,
   Custom = 4,
 }