pgsql: Use the correct PG_DETOAST_DATUM macro in BRIN

Use the correct PG_DETOAST_DATUM macro in BRIN

Commit 6bcda4a721 replaced PG_DETOAST_DATUM with PG_DETOAST_DATUM_PACKED
in two BRIN output functions, for minmax-multi and bloom opclasses. But
this is incorrect - the code is accessing the data through structs that
already include a 4B header, so the detoast needs to match that. But the
PACKED macro may keep the 1B header, which means the struct fields will
point to incorrect data.

Backpatch-through: 16
Discussion: https://postgr.es/m/1df00a66-db5a-4e66-809a-99b386a06d86%40enterprisedb.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bb616ed3e6a2b263be320026e1660bd36827c858

Modified Files
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src/backend/access/brin/brin_bloom.c | 2 +-
src/backend/access/brin/brin_minmax_multi.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)