[IMP] core: make sure addon dir exist before loading

Loading an non-existing addon directory affect all other modules to be
not loaded. This commit makes sure the path exist before proceed to
explore all the modules under that directory.

closes odoo/odoo#104585

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

odoo/modules/module.py

@@ -421,6 +421,9 @@ def get_modules():
 
     plist = []
     for ad in odoo.addons.__path__:
+        if not os.path.exists(ad):
+            _logger.warning("addons path does not exist: %s", ad)
+            continue
         plist.extend(listdir(ad))
     return list(set(plist))