Case coercion of Structs loses field names  #14383

create table t as values
(
 100,                                      -- column1 int (so the case isn't constant folded)
 { 'foo': 'bar' },                         -- column2 has List of Struct w/ Utf8
 { 'foo': arrow_cast('baz', 'Utf8View') }  -- column3 has List of Struct w/ Utf8View
);

 -- fields are correctly names 'foo'
SELECT column2, column3  FROM t;

-- +------------+------------+
-- | column2    | column3    |
-- +------------+------------+
-- | {foo: bar} | {foo: baz} |
-- +------------+------------+
-- 1 row(s) fetched.

-- When coerced the field name turns into `c0` should be `foo`
SELECT case when column1 > 0 then column2 else column3 end FROM t;

-- +------------------------------------------------------------------+
-- | CASE WHEN t.column1 > Int64(0) THEN t.column2 ELSE t.column3 END |
-- +------------------------------------------------------------------+
-- | {c0: bar}                                                        |
-- +------------------------------------------------------------------+

{foo: bar}