Fix memory leak when using the Recent Messages API (#4499)

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Bugfix: Fixed placeholder color in Qt 6. (#4477)
 - Bugfix: Fixed blocked user list being empty when opening the settings dialog for the first time. (#4437)
 - Bugfix: Fixed blocked user list sticking around when switching from a logged in user to being logged out. (#4437)
+- Bugfix: Fixed a memory leak that occurred when loading message history. This was mostly noticeable with unstable internet connections where reconnections were frequent or long-running instances of Chatterino. (#4499)
 - Dev: Disabling precompiled headers on Windows is now tested in CI. (#4472)
 - Dev: Ignore unhandled BTTV user-events. (#4438)
 - Dev: Only log debug messages when NDEBUG is not defined. (#4442)

src/providers/RecentMessagesApi.cpp

@@ -140,6 +140,8 @@ namespace {
                 builtMessage->flags.set(MessageFlag::RecentMessage);
                 allBuiltMessages.emplace_back(builtMessage);
             }
+
+            message->deleteLater();
         }
 
         return allBuiltMessages;