fix(pgsql): Replace DROP TABLE with DROP SCHEMA CASCADE to handle extension-owned tables

[o0Charly0o]

Problem
drush sql-drop silently fails on PostgreSQL databases that have extensions installed (e.g. PostGIS, pgvector).

The current implementation generates:

When PostgreSQL extensions own certain tables (e.g. spatial_ref_sys from PostGIS), attempting to DROP TABLE them raises an error:

Since command() sets ON_ERROR_STOP=1, psql aborts on that error and no tables are dropped — but Drush reports success.

Fix
Replace the per-table DROP TABLE loop with a schema-level reset:

This approach:

Drops all user tables, views, sequences, and extension-owned objects in one atomic operation
Avoids conflicts with extension-managed tables
Restores the schema and grants so Drupal can reinstall immediately after
Testing
Verified on:

PostgreSQL with PostGIS, pg_trgm, and pgvector extensions installed
drush sql-drop -y && drush site:install -y completes successfully

[weitzman]

needs verifying by another postgres user

[weitzman]

This ignores $tables. This will break the table list options on sql commands.