[MM-39583] - Intermediary web login page: Workspace Cookies (#19256)

* [MM-39583] - Intermediary web login page: Workspace Cookies

* only cloud

* fix error with license check

* feedback impl

* improvement

* make improvements

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/session.go

@@ -15,6 +15,7 @@ const (
 	SessionCookieToken            = "MMAUTHTOKEN"
 	SessionCookieUser             = "MMUSERID"
 	SessionCookieCsrf             = "MMCSRF"
+	SessionCookieCloudUrl         = "MMCLOUDURL"
 	SessionCacheSize              = 35000
 	SessionPropPlatform           = "platform"
 	SessionPropOs                 = "os"