core: don't display unsuported image types
core: don't display unsuported image types

If an image type was supported by osbuild-composer but not
cockpit-composer it would still be displayed. Now, an image type must
be listed in the list of imageTypeLabels for it to be displayed in the
list of available image-types.

jkozol/welder-web,jkozol/welder-web,jkozol/welder-web,jkozol/welder-web