manual cherrypick: [MM-67074] Integration Action memory use fix (#34896) (#35089)

Automatic Merge

server/channels/app/integration_action.go

@@ -252,7 +252,8 @@ func (a *App) DoPostActionWithCookie(c request.CTX, postID, actionId, userID, se
 	defer resp.Body.Close()
 
 	var response model.PostActionIntegrationResponse
-	respBytes, err := io.ReadAll(resp.Body)
+	limitedReader := io.LimitReader(resp.Body, MaxIntegrationResponseSize)
+	respBytes, err := io.ReadAll(limitedReader)
 	if err != nil {
 		return "", model.NewAppError("DoPostActionWithCookie", "api.post.do_action.action_integration.app_error", nil, "", http.StatusBadRequest).Wrap(err)
 	}