Recursive JSON seg faults

[dpsimpson]

Describe the issue as clearly as possible:

Parsing a recursive JSON schema seg faults without throwing an error.

Steps/code to reproduce the bug:

import outlines_core.fsm.json_schema
schema = r'{  "type": "object",  "properties": {    "name": { "type": "string" },    "children": {      "type": "array",      "items": { "$ref": "#" }    }  }}'
regex = outlines_core.fsm.json_schema.build_regex_from_schema(schema)

### Expected result:

```shell
Probably an error

Error message:

Segmentation fault (core dumped)

Outlines/Python version information:

Version information

``` 0.1.14 Python 3.12.7 | packaged by Anaconda, Inc. | (main, Oct 4 2024, 13:27:36) [GCC 11.2.0] ```

Context for the issue:

No response