[MM-48542] Removing integration limits (#21282)

* Removing integration limits

* Remove freemium limit test

* Remove test assertion regarding cloud limits

* Remove GetIntegrationsUsage

* Removing integrations usage notifications

* This shouldn't be removed

* Removing client call and websocket event

* Remove old translations

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

model/usage.go

@@ -16,10 +16,6 @@ type TeamsUsage struct {
 	CloudArchived int64 `json:"cloud_archived"`
 }
 
-type IntegrationsUsage struct {
-	Enabled int `json:"enabled"`
-}
-
 var InstalledIntegrationsIgnoredPlugins = map[string]struct{}{
 	PluginIdPlaybooks:     {},
 	PluginIdFocalboard:    {},