[WPE] Unreviewed, fix build for 'WPE_PLATFORM=disabled'

https://bugs.webkit.org/show_bug.cgi?id=299873

Changeset 301049@main added a block of code that uses the functions 'screenData'
and 'primaryScreenDisplayID'. These functions are only defined when 'WPE_PLATFORM'
is enabled.

* Source/WebCore/platform/graphics/gstreamer/GStreamerRegistryScanner.cpp:
(WebCore::GStreamerRegistryScanner::isConfigurationSupported const):

Canonical link: https://commits.webkit.org/301141@main

Author: dpino

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

@@ -1021,6 +1021,7 @@ GStreamerRegistryScanner::RegistryLookupResult GStreamerRegistryScanner::isConfi
             videoConfiguration.bitrate, videoConfiguration.framerate);
 #endif
 
+#if ENABLE(WPE_PLATFORM)
         auto* scrData = screenData(primaryScreenDisplayID());
         if (!scrData || !scrData->screenSupportsHighDynamicRange) {
             // Check HDR metadata field
@@ -1034,6 +1035,7 @@ GStreamerRegistryScanner::RegistryLookupResult GStreamerRegistryScanner::isConfi
                     return { false, false, nullptr };
             }
         }
+#endif
 
         auto contentType = ContentType(videoConfiguration.contentType);
         if (!isContainerTypeSupported(configuration, contentType.containerType()))