[MM-27367] fix ldap group decoding in client (#15192)

Summary

    The data returned by the get ldap groups api endpoint was being decoded incorrectly in the Go client.

Ticket Link

    https://mattermost.atlassian.net/browse/MM-27367

model/client4.go

@@ -3875,7 +3875,19 @@ func (c *Client4) GetLdapGroups() ([]*Group, *Response) {
 	}
 	defer closeBody(r)
 
-	return GroupsFromJson(r.Body), BuildResponse(r)
+	responseData := struct {
+		Count  int      `json:"count"`
+		Groups []*Group `json:"groups"`
+	}{}
+	if err := json.NewDecoder(r.Body).Decode(&responseData); err != nil {
+		appErr := NewAppError("Api4.GetLdapGroups", "api.marshal_error", nil, err.Error(), http.StatusInternalServerError)
+		return nil, BuildErrorResponse(r, appErr)
+	}
+	for i := range responseData.Groups {
+		responseData.Groups[i].DisplayName = *responseData.Groups[i].Name
+	}
+
+	return responseData.Groups, BuildResponse(r)
 }
 
 // LinkLdapGroup creates or undeletes a Mattermost group and associates it to the given LDAP group DN.