CMake: Fix *-metatypes.json creation for non-Ninja generators

This amends commit db90097, which fixed
the *-metatypes.json creation for Makefile generators. User feedback and
the comments in the underlying CMake issue #19005 suggest that all
non-Ninja generators are affected.

Fix this by activating the work-around for all non-Ninja generators.

Pick-to: 6.6 6.5
Fixes: QTBUG-120317
Change-Id: I537ff7be9c658b7053f7f5df6cbced460be43270
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by:  Alexey Edelev <alexey.edelev@qt.io>
(cherry picked from commit 3a4397a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/Qt6CoreMacros.cmake

@@ -1371,7 +1371,7 @@ function(qt6_extract_metatypes target)
         VERBATIM
     )
 
-    if(CMAKE_GENERATOR MATCHES " Makefiles")
+    if(NOT CMAKE_GENERATOR MATCHES "^Ninja")
         # Work around https://gitlab.kitware.com/cmake/cmake/-/issues/19005 to trigger the command
         # that generates ${metatypes_file}.
         add_custom_command(