[Config] canBeEnabled() not properly handling null #25862
Description
| Q | A |
|---|---|
| Bug report? | yes |
| Feature request? | no |
| BC Break report? | yes |
| RFC? | no |
| Symfony version | all not yet released |
#25789 seems to have broken the handling for null values if a (nested) array node can be enabled (this can be easily reproduced by using null instead of the nested enabled node in the changes made in #25847.