MV_MIN


Converts a multivalued field into a single valued field containing the minimum value. For example:
```esql
ROW a=[2, 1]
| EVAL min_a = MV_MIN(a)
```

It can be used by any field type, including keyword fields. In that case picks the
first string, comparing their utf-8 representation byte by byte:
```esql
ROW a=["foo", "bar"]
| EVAL min_a = MV_MIN(a)
```

Supported types:
