MM-36127 Check for emojis in message attachment titles (#17943)

app/post_metadata.go

@@ -270,6 +270,10 @@ func getEmojiNamesForPost(post *model.Post, reactions []*model.Reaction) []strin
 
 	// Post attachments
 	for _, attachment := range post.Attachments() {
+		if attachment.Title != "" {
+			names = append(names, getEmojiNamesForString(attachment.Title)...)
+		}
+
 		if attachment.Text != "" {
 			names = append(names, getEmojiNamesForString(attachment.Text)...)
 		}

app/post_metadata_test.go

@@ -1130,10 +1130,13 @@ func TestGetEmojiNamesForPost(t *testing.T) {
 								},
 							},
 						},
+						{
+							Title: "This is the title: :emoji5:",
+						},
 					},
 				},
 			},
-			Expected: []string{"emoji1", "emoji2", "emoji3", "emoji4"},
+			Expected: []string{"emoji1", "emoji2", "emoji3", "emoji4", "emoji5"},
 		},
 		{
 			Description: "with duplicates",