[9.x] Fix Postgres driver not dropping all tables & views

[derekmd]

Fixes #41483
Replaces #41541

This fixes php artisan db:wipe not dropping all tables & views across multiple Postgres schemas. DROP queries didn't schema-qualify names so only the first object found is dropped. e.g., if a "migrations" table exists in two schemas, Schema::dropAllTables() leaves one of those tables.

Start schema-qualifying these names to ensure each object is explicitly removed.

-- assuming config('database.connections.pgsql.search_path') === 'public,laravel'

-- before
drop table "migrations","users" cascade

-- after
drop table "public"."migrations","public"."users","laravel"."migrations","laravel"."users" cascade

---

This implementation is almost functionality the same as the other draft PR except it:

• simplifies quote-wrapping table/view/type names
• Schema::getAllTables() returns an already-quoted $row['qualifiedname'] column. e.g,

  [
    [
      'tablename' => 'migrations',
      'qualifiedname' => '"laravel"."migrations"',
    ],
    [
      'tablename' => 'users',
      'qualifiedname' => '"laravel"."users"',
    ],
  ]

• adds integration tests to wipe tables & views defined in two separate schemas
• replaces array_walk() expressions from previous PRs with simpler array_map().
• clarifies up some mock andReturn() values from previous PRs

[driesvints]

Thanks @derekmd