`textCase` is missing `ORIGINAL` value

Example response snippet:
```jsonc
"styleOverrideTable": {
    "1": {
      // ...
      "textCase": "ORIGINAL",
    }
  },
```

Current openapi spec:
```yaml
textCase:
    type: string
    description: Text casing applied to the node, default is the original casing.
    enum:
      - UPPER
      - LOWER
      - TITLE
      - SMALL_CAPS
      - SMALL_CAPS_FORCED
```