Revert "Change mail_attachment_detection_options default"

It was accidentally merged too early.

Author: sirainen

data/settings.js

@@ -7344,11 +7344,6 @@ See [[link,mail_cache]] for details and for the list of fields.`
 
 	mail_attachment_detection_options: {
 		values: setting_types.BOOLLIST,
-		default: `
-add-flags "content-type=!application/signature"
-<br /><br />
-[[changed,mail_attachment_detection_options_changed]] The default value was
-added. It used to be empty.`,
 		text: `
 Settings to control adding \`$HasAttachment\` or \`$HasNoAttachment\`
 keywords. By default, all MIME parts with \`Content-Disposition=attachment\`

data/updates.js

@@ -51,7 +51,6 @@ export const updates = {
 	lua_auth_init: '2.4.0',
 	lua_dns_client: '2.4.0',
 	lua_script_init: '2.4.0',
-	mail_attachment_detection_options_changed: '2.4.2',
 	mail_cache_fields_changed: '2.4.1',
 	mail_crypt_eddsa: '2.4.0',
 	mail_crypt_fs_maybe: '2.4.0',

docs/installation/upgrade/2.4-to-2.4.x.md

@@ -36,6 +36,5 @@ changed to `2.4.2`.
 
 | Setting | Old Default Value | New Default Value |
 | ------- | ----------------- | ----------------- |
-| [[setting,mail_attachment_detection_options]] |  | `add-flags content-type=!application/signature` | |
 | `service/anvil/unix_listener/anvil/mode` | `0600` | `0660` |
 | `service/anvil/unix_listener/anvil/group` | (empty = root) | `$SET:default_internal_group` |