`make_array` should support pure null array

### Describe the bug

DataFusion supports now heterogeneous arrays (i.e. containing `NULL` with another data type), but does not support pure null array.

### To Reproduce

DataFusion:

```
❯ select make_array(NULL, NULL, NULL);
+----------------------------+
| make_array(NULL,NULL,NULL) |
+----------------------------+
| [] |
+----------------------------+
```

```
❯ select make_array(NULL, 1, NULL, 2, NULL);
+----------------------------------------------+
| make_array(NULL,Int64(1),NULL,Int64(2),NULL) |
+----------------------------------------------+
| [, 1, , 2, ] |
+----------------------------------------------+
```

### Expected behavior

The output should be equal like in other databases (DuckDB, ClickHouse, PostgreSQL):

DuckDB:

```
D select list_value(NULL, NULL, NULL);
┌──────────────────────────────┐
│ list_value(NULL, NULL, NULL) │
│ int32[] │
├──────────────────────────────┤
│ [NULL, NULL, NULL] │
└──────────────────────────────┘
```

```
D select list_value(NULL, 1, NULL, 2, NULL);
┌────────────────────────────────────┐
│ list_value(NULL, 1, NULL, 2, NULL) │
│ int32[] │
├────────────────────────────────────┤
│ [NULL, 1, NULL, 2, NULL] │
└────────────────────────────────────┘
```

ClickHouse:

```
SELECT [NULL, NULL, NULL]

Query id: fe6008c8-7d4c-4c1e-96c4-852c900e5530

┌─[NULL, NULL, NULL]─┐
│ [NULL,NULL,NULL] │
└────────────────────┘

1 row in set. Elapsed: 0.001 sec.
```

```
SELECT [NULL, 1, NULL, 2, NULL]

Query id: 24391d20-dc13-4624-9df1-befb01edab4a

┌─[NULL, 1, NULL, 2, NULL]─┐
│ [NULL,1,NULL,2,NULL] │
└──────────────────────────┘

1 row in set. Elapsed: 0.001 sec.
```

PostgreSQL:

```
postgres=# select array[NULL, NULL, NULL];
array
------------------
{NULL,NULL,NULL}
(1 row)
```

```
postgres=# select array[NULL, 1, NULL, 2, NULL];
array
----------------------
{NULL,1,NULL,2,NULL}
(1 row)
```

### Additional context

_No response_

Start by locating the make_array implementation and its existing tests in DataFusion, then reproduce both the all-NULL and mixed NULL/non-NULL queries. Update the behavior so pure NULL inputs preserve their elements, and add or adjust tests covering the expected array results.

Written by the indexing model from the issue text.