Fix the namespaceless target condition in __qt_internal_walk_libs

Access the target name value, but not use the variable name in
when checking the target existence.

Pick-to: 6.5 6.2
Change-Id: I0f86e3c7665d9c028bf4cbdc5aa8fb840fe1d542
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
(cherry picked from commit 3d4a5c5)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 0d7784e)

cmake/QtPublicWalkLibsHelpers.cmake

@@ -189,7 +189,7 @@ function(__qt_internal_walk_libs
                     # namespace. Which one is preferred doesn't really matter. This code exists to
                     # avoid ending up with both, Qt::Foo and Foo in our dependencies.
                     set(namespaceless_lib_target "${CMAKE_MATCH_1}")
-                    if(TARGET namespaceless_lib_target)
+                    if(TARGET "${namespaceless_lib_target}")
                         set(lib_target ${namespaceless_lib_target})
                     endif()
                 endif()