[MM-41022] - Fix panic when AllowCookiesSubdomain setting is false (#19339)

* [MM-41022] - Cloud: Panic after log in when AllowCookiesSubdomain setting is false

* remove print

* improvement

* remove configration setting from flow

* fix tests

* feedback impl

* feedback impl

api4/user_test.go

@@ -3643,7 +3643,6 @@ func TestLoginCookies(t *testing.T) {
 
 	t.Run("should return cookie with MMCLOUDURL for cloud installations", func(t *testing.T) {
 		updateConfig := func(cfg *model.Config) {
-			*cfg.ServiceSettings.AllowCookiesForSubdomains = true
 			*cfg.ServiceSettings.SiteURL = "https://testchips.cloud.mattermost.com"
 		}
 		th := SetupAndApplyConfigBeforeLogin(t, updateConfig).InitBasic()
@@ -3661,9 +3660,29 @@ func TestLoginCookies(t *testing.T) {
 		assert.Equal(t, "mattermost.com", domain)
 	})
 
+	t.Run("should NOT return cookie with MMCLOUDURL for cloud installations without expected format of cloud URL", func(t *testing.T) {
+		updateConfig := func(cfg *model.Config) {
+			*cfg.ServiceSettings.SiteURL = "https://testchips.com" // correct cloud URL would be https://testchips.cloud.mattermost.com
+		}
+		th := SetupAndApplyConfigBeforeLogin(t, updateConfig).InitBasic()
+		defer th.TearDown()
+
+		th.App.Srv().SetLicense(model.NewTestLicense("cloud"))
+
+		_, resp, _ := th.Client.Login(th.BasicUser.Email, th.BasicUser.Password)
+
+		cloudSessionCookie := ""
+		for _, cookie := range resp.Header["Set-Cookie"] {
+			if match := regexp.MustCompile("^" + model.SessionCookieCloudUrl + "=([a-z0-9]+)").FindStringSubmatch(cookie); match != nil {
+				cloudSessionCookie = match[1]
+			}
+		}
+		// no cookie set
+		assert.Equal(t, "", cloudSessionCookie)
+	})
+
 	t.Run("should NOT return cookie with MMCLOUDURL for NON cloud installations", func(t *testing.T) {
 		updateConfig := func(cfg *model.Config) {
-			*cfg.ServiceSettings.AllowCookiesForSubdomains = true
 			*cfg.ServiceSettings.SiteURL = "https://testchips.com"
 		}
 		th := SetupAndApplyConfigBeforeLogin(t, updateConfig).InitBasic()