List of structures crashes on out of bounds cases if struct has `null` value

[comphead]

Describe the bug

The query below crashes

> select map_values(map([named_struct('a', 1, 'b', null)], [named_struct('a', 1, 'b', null)]))[0] as a;

thread 'main' panicked at /Users/xxx/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/arrow-array-55.0.0/src/array/null_array.rs:149:9:
NullArray data should not contain a null buffer, as no buffers are required
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

UPD: the problem is more broad and impacts any list of struct if the struct contains a null

> select [named_struct('a', 1, 'b', null)][-2];

thread 'main' panicked at /Users/xxx/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/arrow-array-55.1.0/src/array/null_array.rs:149:9:
NullArray data should not contain a null buffer, as no buffers are required
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The problem is the b field is a NullType, if it is casted to any other type the query returns NULL as expected

It is expected to handle this gracefully, if index is not found it should return NULL

To Reproduce

No response

Expected behavior

No response

Additional context

No response

[krishvishal]

take

[krishvishal]

Hi, this will be my first time contributing to datafusion.

I've made the fix, which now emits the following for problematic queries:

> select map_values(map([named_struct('a', 1, 'b', null)], [named_struct('a', 1, 'b', null)]))[0] as a;
+------+
| a    |
+------+
| NULL |
+------+

> select [named_struct('a', 1, 'b', null)][0] as a;
+------+
| a    |
+------+
| NULL |
+------+
1 row(s) fetched. 
Elapsed 0.005 seconds.

Is this the expected behavior?

[comphead]

Hi, this will be my first time contributing to datafusion.

I've made the fix, which now emits the following for problematic queries:

select map_values(map([named_struct('a', 1, 'b', null)], [named_struct('a', 1, 'b', null)]))[0] as a;
+------+
| a |
+------+
| NULL |
+------+

select [named_struct('a', 1, 'b', null)][0] as a;
+------+
| a |
+------+
| NULL |
+------+
1 row(s) fetched.
Elapsed 0.005 seconds.
Is this the expected behavior?

Thanks @krishvishal lets have a PR and we can discuss the behavior there. But having NULLs if out of bounds happen makes sense to me

[krishvishal]

@comphead I've created a PR: #16203