Fix Groups messages export sanity test (#4775)

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [x] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

src/cmd/sanity_test/export/groups.go

@@ -50,6 +50,20 @@ func CheckGroupsExport(
 		envs)
 }
 
+func removeDeletedMessages(
+	ctx context.Context,
+	tree *common.Sanitree[models.Channelable, models.ChatMessageable],
+) {
+	for _, child := range tree.Children {
+		for _, leaf := range child.Leaves {
+			if leaf.Self.GetDeletedDateTime() != nil {
+				delete(child.Leaves, leaf.ID)
+				child.CountLeaves--
+			}
+		}
+	}
+}
+
 func checkChannelMessagesExport(
 	ctx context.Context,
 	ac api.Client,
@@ -82,6 +96,8 @@ func checkChannelMessagesExport(
 		common.CompareLeaves(ctx, expect.Leaves, updatedResultLeaves, nil)
 	}
 
+	removeDeletedMessages(ctx, sourceTree)
+
 	common.CompareDiffTrees(
 		ctx,
 		sourceTree,
@@ -146,6 +162,7 @@ func populateMessagesSanitree(
 		}
 
 		for _, msg := range filteredMsgs {
+			child.CountLeaves++
 			child.Leaves[ptr.Val(msg.GetId())] = &common.Sanileaf[
 				models.Channelable,
 				models.ChatMessageable,