Proxy: Change string

No Proxy meant that Gajim is not overriding a system configured proxy.

System makes this more clear.

gajim/gtk/accounts.py

@@ -787,7 +787,7 @@ def __init__(self, account):
             Setting(SettingKind.POPOVER, _('Proxy'),
                     SettingType.ACCOUNT_CONFIG, 'proxy', name='proxy',
                     props={'entries': self._get_proxies(),
-                           'default-text': _('No Proxy'),
+                           'default-text': _('System'),
                            'button-icon-name': 'preferences-system-symbolic',
                            'button-callback': self._on_proxy_edit}),
 

gajim/gtk/preferences.py

@@ -983,7 +983,7 @@ def __init__(self, pref_window):
                     'global_proxy',
                     name='global_proxy',
                     props={'entries': self._get_proxies(),
-                           'default-text': _('No Proxy'),
+                           'default-text': _('System'),
                            'button-icon-name': 'preferences-system-symbolic',
                            'button-callback': self._on_proxy_edit}),