pgsql: Fix overly strict Assert in jsonpath code

Fix overly strict Assert in jsonpath code

This was failing for queries which try to get the .type() of a
jpiLikeRegex. For example:

select jsonb_path_query('["string", "string"]',
'($[0] like_regex ".{7}").type()');

Reported-by: Alexander Kozhemyakin
Bug: #18035
Discussion: https://postgr.es/m/[email protected]
Backpatch-through: 12, where SQL/JSON path was added.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/deae1657ee6dd6f7b3effab3d44429d5434f5bbf

Modified Files
--------------
src/backend/utils/adt/jsonpath.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)