[SyliusWebBundle] Fix invalid ApiBundle "UpdatedAt" field in macros twig

Hi,

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

Small fix to prevent list error when adding API key