package/libcamera: latest update missed the Qt5 to Qt6 change

Latest update

72757d111a package/libcamera: bump to version 0.3.2 ([1])

missed the Qt5 to Qt6 change, see [2]

- apps: qcam: Port to Qt 6

and [3].

[1] 72757d11

[2] https://git.libcamera.org/libcamera/libcamera.git/tag/?h=v0.3.1

[3] https://git.libcamera.org/libcamera/libcamera.git/commit/?id=71aa3ceec30b152fe5a02aba968c8c72cb47149e