[MM-67157] Remove format parameter requirement from client license endpoint (#37167)

* MM-67157: Remove unused format flag from /license/client endpoint

The `format` query parameter on the `/license/client` (and local
variant) endpoint was effectively dead: it was required but only ever
accepted the single value `old`, returning an error otherwise. This
mirrors the earlier removal of the same flag from `/config/client`,
where the server now ignores the parameter while clients continue to
send `format=old` for compatibility with pre-v11 servers.

The server no longer inspects the `format` parameter, so requests with
no format, `format=old`, or any other value all succeed. The unused
i18n string and the parameter/response documentation in the OpenAPI
spec are removed accordingly.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Audz4JLNQN5SJxcPwyQBd

* MM-67157: document format=old retention in webapp client

Mirror the getClientConfig comment so the format=old query param on
getClientLicenseOld is not mistakenly removed; clients keep sending it
for compatibility with pre-v11 servers even though current servers now
ignore it.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Audz4JLNQN5SJxcPwyQBd

* MM-67157: stop sending format=old from webapp client

Now that the server ignores the format parameter on /license/client,
drop format=old from the @mattermost/client getClientLicenseOld call and
update the e2e intercepts/helpers that matched the old query string.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Audz4JLNQN5SJxcPwyQBd

* Drop unneeded wildcard from license/client cy.intercept path

The format query param is gone from GET /license/client requests, so
the trailing * used to match it is no longer needed.

---------

Co-authored-by: Claude <noreply@anthropic.com>

server/channels/api4/license.go

@@ -28,18 +28,6 @@ func (api *API) InitLicense() {
 }
 
 func getClientLicense(c *Context, w http.ResponseWriter, r *http.Request) {
-	format := r.URL.Query().Get("format")
-
-	if format == "" {
-		c.Err = model.NewAppError("getClientLicense", "api.license.client.old_format.app_error", nil, "", http.StatusBadRequest)
-		return
-	}
-
-	if format != "old" {
-		c.SetInvalidParam("format")
-		return
-	}
-
 	var clientLicense map[string]string
 
 	if c.App.SessionHasPermissionTo(*c.AppContext.Session(), model.PermissionReadLicenseInformation) {

server/channels/api4/license_local.go

@@ -103,18 +103,6 @@ func localRemoveLicense(c *Context, w http.ResponseWriter, r *http.Request) {
 }
 
 func localGetClientLicense(c *Context, w http.ResponseWriter, r *http.Request) {
-	format := r.URL.Query().Get("format")
-
-	if format == "" {
-		c.Err = model.NewAppError("localGetClientLicense", "api.license.client.old_format.app_error", nil, "", http.StatusBadRequest)
-		return
-	}
-
-	if format != "old" {
-		c.SetInvalidParam("format")
-		return
-	}
-
 	clientLicense := c.App.Srv().ClientLicense()
 
 	if _, err := w.Write([]byte(model.MapToJSON(clientLicense))); err != nil {

server/channels/api4/license_test.go

@@ -38,14 +38,12 @@ func TestGetOldClientLicense(t *testing.T) {
 	require.NoError(t, err)
 
 	resp, err := client.DoAPIGet(context.Background(), "/license/client", "")
-	require.Error(t, err, "get /license/client did not return an error")
-	require.Equal(t, http.StatusBadRequest, resp.StatusCode,
-		"expected 400 bad request")
+	require.NoError(t, err, "get /license/client should not return an error")
+	require.Equal(t, http.StatusOK, resp.StatusCode, "expected 200 OK")
 
 	resp, err = client.DoAPIGet(context.Background(), "/license/client?format=junk", "")
-	require.Error(t, err, "get /license/client?format=junk did not return an error")
-	require.Equal(t, http.StatusBadRequest, resp.StatusCode,
-		"expected 400 Bad Request")
+	require.NoError(t, err, "get /license/client?format=junk should not return an error")
+	require.Equal(t, http.StatusOK, resp.StatusCode, "expected 200 OK")
 
 	license, _, err = th.SystemAdminClient.GetOldClientLicense(context.Background(), "")
 	require.NoError(t, err)

server/i18n/en.json

@@ -2700,10 +2700,6 @@
     "id": "api.license.add_license.wrong_environment_test.app_error",
     "translation": "This is a test or development license, but this server is running in a production environment. Test or development licenses can only be used on test or development servers."
   },
-  {
-    "id": "api.license.client.old_format.app_error",
-    "translation": "New format for the client license is not supported yet. Please specify format=old in the query string."
-  },
   {
     "id": "api.license.load_metric.app_error",
     "translation": "Failed to compute monthly active users."