externalsrc: Pass through npmsw URIs in SRC_URI

NPM shrinkwrap files need to stay in SRC_URI even when using
externalsrc so that npm_do_fetch can run to fetch the required
dependencies.

(From OE-Core rev: b8eb2e7d5c13e617aea6083567870a0de5cc6e42)

Signed-off-by: Mike Crowe <mac@mcrowe.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit e889cbecf9a1731b199e57d79a14e574398586bb)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/externalsrc.bbclass

@@ -68,6 +68,7 @@ python () {
             url_data = fetch.ud[url]
             parm = url_data.parm
             if (url_data.type == 'file' or
+                    url_data.type == 'npmsw' or
                     'type' in parm and parm['type'] == 'kmeta'):
                 local_srcuri.append(url)