This field is used to store gbooleans (which are ints) but if it's
a :1 bit depth assigning ints to it changes it's value as the only
valid values are -1 and 0.
Make it a guint instead so the cast would be correct.
```
../subprojects/gst-plugins-bad/gst-libs/gst/vulkan/xcb/gstvkwindow_xcb.c:151:25: error:
implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1
[-Werror,-Wsingle-bit-bitfield-constant-conversion]
window_xcb->visible = TRUE;
```
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5432>