MM-59360 add telemetry for paid features related to guests (#28295)

* add telemetry for paid features related to guests

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/channel.go

@@ -13,6 +13,7 @@ import (
 	"strings"
 
 	"github.com/mattermost/mattermost/server/v8/channels/utils"
+	"github.com/mattermost/mattermost/server/v8/platform/services/telemetry"
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/plugin"
@@ -1568,6 +1569,13 @@ func (a *App) addUserToChannel(c request.CTX, user *model.User, channel *model.C
 		return nil, model.NewAppError("AddUserToChannel", "app.channel_member_history.log_join_event.internal_error", nil, "", http.StatusInternalServerError).Wrap(nErr)
 	}
 
+	if user.IsGuest() {
+		a.Srv().telemetryService.SendTelemetryForFeature(
+			telemetry.TrackGuestFeature,
+			"add_guest_to_channel",
+			map[string]any{"user_actual_id": user.Id})
+	}
+
 	a.Srv().Platform().InvalidateChannelCacheForUser(user.Id)
 	a.invalidateCacheForChannelMembers(channel.Id)