DEV: Remove old secure_media setting (#20259)

This has been renamed to secure_uploads since
8ebd5edd1e

config/locales/server.en.yml

@@ -2243,11 +2243,8 @@ en:
     bootstrap_mode_min_users: "Minimum number of users required to disable bootstrap mode (set to 0 to disable)"
 
     prevent_anons_from_downloading_files: "Prevent anonymous users from downloading attachments."
-    secure_media: "DEPRECATED: Use the secure_uploads setting instead, will be removed in Discourse 3.0."
     secure_uploads: 'Limits access to ALL uploads (images, video, audio, text, pdfs, zips, and others). If "login required” is enabled, only logged-in users can access uploads. Otherwise, access will be limited only for media uploads in private messages and private categories. WARNING: This setting is complex and requires deep administrative understanding. See <a target="_blank" href="https://meta.discourse.org/t/-/140017">the secure uploads topic on Meta</a> for details.'
-    secure_media_allow_embed_images_in_emails: "DEPRECATED: Use secure_uploads_allow_embed_images_in_emails, will remove in Discourse 3.0."
     secure_uploads_allow_embed_images_in_emails: "Allows embedding secure images that would normally be redacted in emails, if their size is smaller than the 'secure uploads max email embed image size kb' setting."
-    secure_media_max_email_embed_image_size_kb: "DEPRECATED: Use secure_uploads_max_email_embed_image_size_kb, will be removed in Discourse 3.0."
     secure_uploads_max_email_embed_image_size_kb: "The size cutoff for secure images that will be embedded in emails if the 'secure uploads allow embed in emails' setting is enabled. Without that setting enabled, this setting has no effect."
     slug_generation_method: "Choose a slug generation method. 'encoded' will generate percent encoding string. 'none' will disable slug at all."
 

config/site_settings.yml

@@ -1395,18 +1395,6 @@ files:
   prevent_anons_from_downloading_files:
     default: false
     client: true
-  secure_media:
-    default: false
-    client: true
-    hidden: true
-  secure_media_allow_embed_images_in_emails:
-    default: true
-    hidden: true
-  secure_media_max_email_embed_image_size_kb:
-    default: 1024
-    min: 1
-    max: 10240
-    hidden: true
   secure_uploads:
     default: false
     client: true

lib/site_settings/deprecated_settings.rb

@@ -10,19 +10,6 @@ module SiteSettings::DeprecatedSettings
     ["default_categories_regular", "default_categories_normal", true, "3.0"],
     ["min_trust_to_send_messages", "personal_message_enabled_groups", false, "3.0"],
     ["enable_personal_messages", "personal_message_enabled_groups", false, "3.0"],
-    ["secure_media", "secure_uploads", true, "3.0"],
-    [
-      "secure_media_allow_embed_images_in_emails",
-      "secure_uploads_allow_embed_images_in_emails",
-      true,
-      "3.0",
-    ],
-    [
-      "secure_media_max_email_embed_image_size_kb",
-      "secure_uploads_max_email_embed_image_size_kb",
-      true,
-      "3.0",
-    ],
   ]
 
   def setup_deprecated_methods