Fix invalid input to foreach

[ricardo118]

This happens with discord oauth, possibly others

[rhukster]

Thanks for the fix. I actually prefer a slightly different approach for these scenarios:

$user_groups = Grav::instance()['user_groups'] ?? [];

That way the original loop can be left without adding more nesting.

[rhukster]

Thanks for the fix. I actually prefer a slightly different approach for these scenarios:

$user_groups = Grav::instance()['user_groups'] ?? [];

That way the original loop can be left without adding more nesting.