When a default processor was used, the provided type was bool|int|float|string|array
It was too wide when validated by a scalarNode.

For example, switching a config from :

scalar_node: "%env(FOO_ENV)%"

to :

scalar_node: "%env(default:foo_param:FOO_ENV)%"

Would throw this exception :

[Symfony\Component\Config\Definition\Exception\InvalidTypeException]         
 Invalid type for path "scalar_node". Expected one of "bool", "int", "float", "string", but got one of "bool", "int", "float", "string", "array".    

This fix narrows the provided type to the combination of the parameter and the environment variable types.