fix[array]: min_max return type non nullable

Signed-off-by: Joe Isaacs <[email protected]>

Author: joseph-isaacs

vortex-array/src/compute/min_max.rs

@@ -111,8 +111,8 @@ impl ComputeFnVTable for MinMax {
             StructFields::new(
                 ["min", "max"].into(),
                 vec![
-                    array.dtype().as_nonnullable().clone(),
-                    array.dtype().as_nonnullable().clone(),
+                    array.dtype().as_nonnullable(),
+                    array.dtype().as_nonnullable(),
                 ],
             ),
             Nullability::Nullable,