Remove last remnants of Qt5MacExtras

MacExtras has been both obsoleted by Qt5 and unused by Wireshark code.
https://doc.qt.io/qt-5/qtmac-obsolete.html

CMakeLists.txt

@@ -1250,7 +1250,6 @@ if(BUILD_wireshark)
 		Qt5Widgets
 	)
 	if(APPLE)
-		list(APPEND QT_PACKAGELIST Qt5MacExtras)
 		ws_find_package(Sparkle ENABLE_SPARKLE HAVE_SOFTWARE_UPDATE)
 	endif()
 	if(WIN32)
@@ -1272,9 +1271,6 @@ if(BUILD_wireshark)
 		list(APPEND QT_INCLUDE_DIRS /usr/local/opt/qt5/include)
 	endif()
 	set(QT_FOUND ON)
-	if(Qt5MacExtras_FOUND)
-		set(QT_MACEXTRAS_LIB 1)
-	endif()
 endif()
 
 # MaxMind DB address resolution

cmakeconfig.h.in

@@ -283,9 +283,6 @@
 /* Define if we have QtMultimedia */
 #define QT_MULTIMEDIA_LIB 1
 
-/* Define if we have QtMacExtras */
-#cmakedefine QT_MACEXTRAS_LIB 1
-
 /* Build androiddump with libpcap instead of wireshark stuff */
 #cmakedefine ANDROIDDUMP_USE_LIBPCAP 1