DEV: Move min_trust_to_post_embedded_media to group setting (#25238)

c.f. https://meta.discourse.org/t/we-are-changing-giving-access-to-features/283408

db/post_migrate/20240112043325_fill_embedded_media_post_allowed_groups_based_on_deprecated_setting.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class FillEmbeddedMediaPostAllowedGroupsBasedOnDeprecatedSetting < ActiveRecord::Migration[7.0]
+  def up
+    old_setting_trust_level =
+      DB.query_single(
+        "SELECT value FROM site_settings WHERE name = 'min_trust_to_post_embedded_media' LIMIT 1",
+      ).first
+
+    if old_setting_trust_level.present?
+      allowed_groups = "1#{old_setting_trust_level}"
+
+      DB.exec(
+        "INSERT INTO site_settings(name, value, data_type, created_at, updated_at)
+        VALUES('embedded_media_post_allowed_groups', :setting, '20', NOW(), NOW())",
+        setting: allowed_groups,
+      )
+    end
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end