DEV: Create unlogged tables by default in the test environment (#25451)

Why this change?

In https://www.postgresql.org/docs/current/non-durability.html, it is
recommended to create unlogged tables to avoid WAL writes which can help
speed at performance at the expense of durability. In the CI env, there is no need for durability at all.
Therefore, we are going to be creating unlogged tables by default.

Co-authored-by: Ted Johansson <ted@discourse.org>
Co-authored-by: Rafael dos Santos Silva <xfalcox@gmail.com>

.github/workflows/tests.yml

@@ -145,6 +145,7 @@ jobs:
             ${{ runner.os }}-
             ${{ hashFiles('.github/workflows/tests.yml') }}-
             ${{ hashFiles('db/**/*', 'plugins/**/db/**/*') }}-
+            ${{ hashFiles('config/environments/test.rb') }}-
             ${{ env.USES_PARALLEL_DATABASES }}
 
       - name: Restore database from cache

config/environments/test.rb

@@ -104,4 +104,10 @@ Discourse::Application.configure do
 
     SiteSetting.refresh!
   end
+
+  if ENV["CI"].present?
+    config.to_prepare do
+      ActiveSupport.on_load(:active_record_postgresqladapter) { self.create_unlogged_tables = true }
+    end
+  end
 end