[5.5] Modify except collection method to have a single dimension collection

[amaelftah]

this PR reverts #22399 , the reason is to make the method API consistent

in the documentation except() method accepts single dimension array of keys , not multi dimension array

$collection = collect(['product_id' => 1, 'price' => 100, 'discount' => false]);

//will return all the $collection which is wrong
$collection->except(['price'  => 50, 'discount' => true]);

//same will happen if we do this
 $collection->except(collect(['price' ,'discount' ]));

so in my opinion if we are passing array of keys , we should also pass collection of keys

$collection->except(['price' ,'discount']);

$collection->except(collect(['price' ,'discount']));

[taylorotwell]

This is a breaking change.