UBERF-18: add reactions for comments (#3899)

Signed-off-by: Kristina Fefelova <kristin.fefelova@gmail.com>

plugins/activity-resources/src/utils.ts

@@ -1,4 +1,4 @@
-import type { DisplayTx, TxViewlet } from '@hcengineering/activity'
+import type { ActivityExtension, DisplayTx, TxViewlet } from '@hcengineering/activity'
 import core, {
   AttachedDoc,
   Class,
@@ -426,3 +426,7 @@ function filterCollectionTx (tx: DisplayTx): DisplayTx | undefined {
   }
   return ctx
 }
+
+export async function getExtensions (client: Client, ofClass: Ref<Class<Doc>>): Promise<ActivityExtension[]> {
+  return await client.findAll(activity.class.ActivityExtension, { ofClass })
+}