The addComponentToLayout config action should support adding multiple components

PHPstan doesn't like this:

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  Line   core/modules/layout_builder/src/Plugin/ConfigAction/AddComponent.php  
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  96     Undefined variable: $value                                            
         🪪 variable.undefined                                                 
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 [ERROR] Found 1 error    

Thanks for fixing that. Since it is a bug, it doesn't need a change record. I will add an issue to update our documentation when this lands.

Marking as RTBC.

@phenaproxima pinged me about this as the author of the original action, this looks great to me.