Fix error: comparison of unsigned expression in ‘< 0’ is always false…

… [-Werror=type-limits]

Summary:
Fix OSS build failure: https://github.com/facebookincubator/velox/actions/runs/9354921916/job/25748893926

```
/home/runner/work/velox/velox/velox/./velox/functions/prestosql/SIMDJsonFunctions.h:192:36: error: comparison of unsigned expression in ‘< 0’ is always false [-Werror=type-limits]
  192 |     } else if (numElements + index < 0) {
      |                ~~~~~~~~~~~~~~~~~~~~^~~
cc1plus: all warnings being treated as errors
```

Reviewed By: Yuhta

Differential Revision: D58100041

fbshipit-source-id: 139abaf74e901bcbe9aa7ea6096067d314e4d7b2

velox/functions/prestosql/SIMDJsonFunctions.h

@@ -173,7 +173,7 @@ struct SIMDJsonArrayGetFunction {
       if (index >= numElements) {
         return false;
       }
-    } else if (numElements + index < 0) {
+    } else if ((int64_t)numElements + index < 0) {
       return false;
     } else {
       index += numElements;