Remove duplicate option in admin screen and now-unused translation keys (#28492)

Resolves https://github.com/go-gitea/gitea/issues/28451.

This change follows the recommendation by wxiaoguang to remove the
"Disable Minimum Key Size Check" from the "Service Configuration"
section of the UI, because this option belongs to the "SSH
Configuration" section of the administration menu and already has a
functioning indicator in that section of the UI.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

options/locale/locale_en-US.ini

@@ -3080,7 +3080,6 @@ config.enable_openid_signin = Enable OpenID Sign-In
 config.show_registration_button = Show Register Button
 config.require_sign_in_view = Require Sign-In to View Pages
 config.mail_notify = Enable Email Notifications
-config.disable_key_size_check = Disable Minimum Key Size Check
 config.enable_captcha = Enable CAPTCHA
 config.active_code_lives = Active Code Lives
 config.reset_password_code_lives = Recover Account Code Expiry Time

templates/admin/config.tmpl

@@ -151,8 +151,6 @@
 				<dd>{{if .Service.RequireSignInView}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				<dt>{{ctx.Locale.Tr "admin.config.mail_notify"}}</dt>
 				<dd>{{if .Service.EnableNotifyMail}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
-				<dt>{{ctx.Locale.Tr "admin.config.disable_key_size_check"}}</dt>
-				<dd>{{if .SSH.MinimumKeySizeCheck}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				<dt>{{ctx.Locale.Tr "admin.config.enable_captcha"}}</dt>
 				<dd>{{if .Service.EnableCaptcha}}{{svg "octicon-check"}}{{else}}{{svg "octicon-x"}}{{end}}</dd>
 				<dt>{{ctx.Locale.Tr "admin.config.default_keep_email_private"}}</dt>