fix: qt icons not available when installed as python package

follow-up #5053

setup.py

@@ -47,7 +47,7 @@ if platform.system() in ['Linux', 'FreeBSD', 'DragonFly']:
             usr_share = os.path.expanduser('~/.local/share')
     data_files += [
         (os.path.join(usr_share, 'applications/'), ['electrum.desktop']),
-        (os.path.join(usr_share, icons_dirname), ['icons/electrum.png'])
+        (os.path.join(usr_share, icons_dirname), ['icons/electrum.png']),
     ]
 
 extras_require = {
@@ -79,6 +79,9 @@ setup(
             'wordlist/*.txt',
             'locale/*/LC_MESSAGES/electrum.mo',
         ],
+        'electrum.gui': [
+            'icons/*',
+        ],
     },
     scripts=['electrum/electrum'],
     data_files=data_files,