[GStreamer] Memory leak in GStreamerSinksWorkarounds

https://bugs.webkit.org/show_bug.cgi?id=278989

Reviewed by Alicia Boya Garcia.

* Source/WebCore/platform/graphics/gstreamer/GStreamerSinksWorkarounds.cpp:
(WebCore::AppSinkFlushCapsWorkaroundProbe::checkIsNeeded): Make sure the string allocated in
gst_plugins_base_version_string() is de-allocated afterwards.

Canonical link: https://commits.webkit.org/283051@main

Author: philn

Source/WebCore/platform/graphics/gstreamer/GStreamerSinksWorkarounds.cpp

@@ -204,7 +204,10 @@ class AppSinkFlushCapsWorkaroundProbe {
             return false;
         }
 
-        GST_DEBUG("AppSinkFlushCapsWorkaroundProbe: gst-plugins-base version is %s, bug was fixed in 1.21.1 and backported to 1.20.3.", gst_plugins_base_version_string());
+#ifndef GST_DISABLE_GST_DEBUG
+        GUniquePtr<char> version(gst_plugins_base_version_string());
+        GST_DEBUG("AppSinkFlushCapsWorkaroundProbe: gst-plugins-base version is %s, bug was fixed in 1.21.1 and backported to 1.20.3.", version.get());
+#endif
         WorkaroundMode mode = getWorkAroundModeFromEnvironment("WEBKIT_GST_WORKAROUND_APP_SINK_FLUSH_CAPS", WEBKIT_GST_WORKAROUND_APP_SINK_FLUSH_CAPS_DEFAULT_MODE);
         if (mode == WorkaroundMode::ForceEnable) {
             GST_DEBUG("AppSinkFlushCapsWorkaroundProbe: forcing workaround to be enabled.");