arrow

MINOR: [C++] Fix unity build error (#14083)

```
/arrow/cpp/src/arrow/compute/exec/bloom_filter.h:252:25: error: type attributes ignored after type is already defined [-Werror=attributes]
  252 | enum class ARROW_EXPORT BloomFilterBuildStrategy {
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~
```

Authored-by: David Li <li.davidm96@gmail.com>
Signed-off-by: David Li <li.davidm96@gmail.com>