CMake: Always execute qt_find_package(MODULE) calls

A qt_find_package(Foo MODULE) call is only executed if Foo_FOUND is 0,
otherwise it is skipped.

This is problematic for FindFoo scripts that are implemented
using pkg_check_modules calls which specify a <prefix> that matches
the package name (Foo), because pkg_check_modules then sets the
Foo_FOUND cache var to 1.

On reconfiguration Foo_FOUND is 1, the qt_find_package call is
skipped, and thus no targets are created, which can lead to
'unknown target' errors.

The fact that pkg_check_modules sets a cache var, rather than a local
var is a CMake issue:
https://gitlab.kitware.com/cmake/cmake/-/issues/27014

One workaround would be to modify all our Find scripts to use a
<prefix> that does not match the package name, so the _FOUND cache var
is not set. That is somewhat error prone though, and requires some
effort.

Until CMake changes its behavior, make sure we always run
qt_find_package(MODULE) calls, even if the cache var is set as found.

Pick-to: 6.10
Task-number: QTBUG-137870
Change-Id: Ifad8807fd69a65be8e338695b9002760c6d97461
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

cmake/QtFindPackageHelpers.cmake

@@ -136,7 +136,7 @@ macro(qt_find_package)
     # TODO: Handle packages with components where a previous component is already found.
     # E.g. find_package(Qt6 COMPONENTS BuildInternals) followed by
     # qt_find_package(Qt6 COMPONENTS Core) doesn't end up calling find_package(Qt6Core).
-    if (NOT ${ARGV0}_FOUND AND NOT _qt_find_package_skip_find_package)
+    if ((NOT ${ARGV0}_FOUND OR arg_MODULE) AND NOT _qt_find_package_skip_find_package)
         # Call original function without our custom arguments.
         find_package(${arg_UNPARSED_ARGUMENTS})
     endif()