Move HTTP service to public for plugin use (#27284)

* Move httpservice for use in plugins

* Adapt httpservice for plugin use

* Fix lint

server/platform/services/telemetry/telemetry.go

@@ -16,10 +16,10 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/plugin"
+	"github.com/mattermost/mattermost/server/public/shared/httpservice"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 	"github.com/mattermost/mattermost/server/v8/channels/utils"
-	"github.com/mattermost/mattermost/server/v8/platform/services/httpservice"
 	"github.com/mattermost/mattermost/server/v8/platform/services/marketplace"
 	"github.com/mattermost/mattermost/server/v8/platform/services/searchengine"
 )