disallow alter individual column if partition key contains wholerow reference

hi.

while reviewing disallow generated column as partition key in [1],
I found out this bug.

demo:
drop table if exists t4;
CREATE TABLE t4(f1 int, f2 bigint) PARTITION BY list ((t4));
create table t4_1 partition of t4 for values in ((1,2));
alter table t4 alter column f2 set data type text using f2;

insert into t4 select 1, '2';
ERROR: invalid memory alloc request size 18446744073709551615

turns out the fix seems pretty simple, mainly on has_partition_attrs.
has_partition_attrs is used to
Checks if any of the 'attnums' is a partition key attribute for rel.
if partition keys have column references, then has_partition_attrs
should return true.

[1]: https://postgr.es/m/CACJufxF=WDGthXSAQr9thYUsfx_1_t9E6N8tE3B8EqXcVoVfQw@mail.gmail.com