[MM-27967] api4/config_test: fix flaky test if siteurl is already set (#15403)

* api4/config_test: fix flaky test if siteurl is already set

* api4/apitelib enforce siteurl not set

api4/apitestlib.go

@@ -117,6 +117,7 @@ func setupTestHelper(dbStore store.Store, searchEngine *searchengine.Broker, ent
 		*cfg.TeamSettings.MaxUsersPerTeam = 50
 		*cfg.RateLimitSettings.Enable = false
 		*cfg.EmailSettings.SendEmailNotifications = true
+		*cfg.ServiceSettings.SiteURL = ""
 
 		// Disable sniffing, otherwise elastic client fails to connect to docker node
 		// More details: https://github.com/olivere/elastic/wiki/Sniffing

api4/config_test.go

@@ -4,7 +4,6 @@
 package api4
 
 import (
-	"fmt"
 	"net/http"
 	"os"
 	"strings"
@@ -146,7 +145,7 @@ func TestUpdateConfig(t *testing.T) {
 		require.Equal(t, SiteName, cfg.TeamSettings.SiteName, "It should update the SiteName")
 
 		t.Run("Should set defaults for missing fields", func(t *testing.T) {
-			_, appErr := th.SystemAdminClient.DoApiPut(th.SystemAdminClient.GetConfigRoute(), fmt.Sprintf(`{"ServiceSettings":{"SiteURL":"%s"}}`, *cfg.ServiceSettings.SiteURL))
+			_, appErr := th.SystemAdminClient.DoApiPut(th.SystemAdminClient.GetConfigRoute(), "{}")
 			require.Nil(t, appErr)
 		})