Minor: remove stray println! from array_expressions.rs

[alamb]

Which issue does this PR close?

This appears to have crept in as part of #7313

Rationale for this change

when I run sqllogictest it looks like

Running "nullif.slt"
Running "array.slt"
Running "type_coercion.slt"
Running "clickbench.slt"
Running "information_schema_columns.slt"
Running "information_schema_multiple_catalogs.slt"
args[0]: ListArray
[
  PrimitiveArray<Int64>
[
  1,
],
]
args[0]: ListArray
[
  NullArray(0),
]
...
  PrimitiveArray<Int64>
[
  null,
  18,
],
],
]

Compilation finished at Wed Aug 23 14:32:11

What changes are included in this PR?

delete println!

Are these changes tested?

existing tests

Are there any user-facing changes?

[viirya]

Thank you @alamb