introspection: use obj_description/col_description in postgres

[aqrln]

Summary

Use obj_description and col_description functions instead of manual joining on pg_description:

• Fix OID conflicts in CockroachDB for views, columns and enums
• Use obj_description in table queries for consistency (OID conflicts were fixed there in other way in fix(introspection): Add filter for oid class to PostgreSQL tables queries for description #4055)

Description

When searching for database comments in pg_description catalog, our introspection queries for Postgres assumed that OIDs of different objects are unique, but in fact they are only unique in the containing catalog for this type of objects and not throughout the whole database. The assumption often holds true in practice in PostgreSQL because the OID generation algorithm tries to keep them separated and they only start overlapping in very big databases, however CockroachDB uses simpler IDs so they are ambiguous right away.

This issue was uncovered as CockroachDB 23 added descriptions for all built-in functions, so our introspection queries started picking them up when searching for descriptions of tables, columns, views and enums.

#4055 partially fixed this in table queries by filtering by classoid in addition to objoid. It wasn't fixed in view, column and enum queries, as we learned when we tried to add CRDB 23 to CI in #4132 and it showed that some tests were failing because descriptions of random built-in functions were attached to unrelated views.

This PR fixes the issue by using comment information functions instead of joining the pg_description catalog manually.

Closes: prisma/prisma#19935
Ref: #4135
Ref: #4132

[codspeed-hq]

CodSpeed Performance Report

Merging #4136 will not alter performance

_{Comparing integration/obj-description (facb547) with main (9fe3fe4)}

Summary

✅ 11 untouched benchmarks

[Jolg42]

We should see the comments on the views disappear from introspection-ci after this.

[tomhoule]

💯