Passed the config when building the Configuration in ConfigurableExtension

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

This passes the config to ``getConfiguration`` instead of passing an empty array in ConfigurableExtension. This makes the class usable for bundle overwriting the ``getConfiguration`` method to use the config instead of using the default logic (which does not need the config).