UX: Use a dropdown for SSL mode for group SMTP (#27932)

Our old group SMTP SSL option was a checkbox,
but this was not ideal because there are actually
3 different ways SSL can be used when sending
SMTP:

* None
* SSL/TLS
* STARTTLS

We got around this before with specific overrides
for Gmail, but it's not flexible enough and now people
want to use other providers. It's best to be clear,
though it is a technical detail. We provide a way
to test the SMTP settings before saving them so there
should be little chance of messing this up.

This commit also converts GroupEmailSettings to a glimmer
component.

app/controllers/groups_controller.rb

@@ -715,7 +715,6 @@ class GroupsController < ApplicationController
     params.require(:host)
     params.require(:username)
     params.require(:password)
-    params.require(:ssl)
 
     group = Group.find(params[:group_id])
     guardian.ensure_can_edit!(group)
@@ -723,7 +722,6 @@ class GroupsController < ApplicationController
     RateLimiter.new(current_user, "group_test_email_settings", 5, 1.minute).performed!
 
     settings = params.except(:group_id, :protocol)
-    enable_tls = settings[:ssl] == "true"
     email_host = params[:host]
 
     if !%w[smtp imap].include?(params[:protocol])
@@ -734,13 +732,19 @@ class GroupsController < ApplicationController
       begin
         case params[:protocol]
         when "smtp"
-          enable_starttls_auto = false
-          settings.delete(:ssl)
+          raise Discourse::InvalidParameters if params[:ssl_mode].blank?
+
+          settings.delete(:ssl_mode)
+
+          if params[:ssl_mode].blank? ||
+               !Group.smtp_ssl_modes.values.include?(params[:ssl_mode].to_i)
+            raise Discourse::InvalidParameters.new("SSL mode must be present and valid")
+          end
 
           final_settings =
             settings.merge(
-              enable_tls: enable_tls,
-              enable_starttls_auto: enable_starttls_auto,
+              enable_tls: params[:ssl_mode].to_i == Group.smtp_ssl_modes[:ssl_tls],
+              enable_starttls_auto: params[:ssl_mode].to_i == Group.smtp_ssl_modes[:starttls],
             ).permit(:host, :port, :username, :password, :enable_tls, :enable_starttls_auto, :debug)
           EmailSettingsValidator.validate_as_user(
             current_user,
@@ -748,8 +752,17 @@ class GroupsController < ApplicationController
             **final_settings.to_h.symbolize_keys,
           )
         when "imap"
+          raise Discourse::InvalidParameters if params[:ssl].blank?
+
           final_settings =
-            settings.merge(ssl: enable_tls).permit(:host, :port, :username, :password, :ssl, :debug)
+            settings.merge(ssl: settings[:ssl] == "true").permit(
+              :host,
+              :port,
+              :username,
+              :password,
+              :ssl,
+              :debug,
+            )
           EmailSettingsValidator.validate_as_user(
             current_user,
             "imap",
@@ -812,7 +825,7 @@ class GroupsController < ApplicationController
         :incoming_email,
         :smtp_server,
         :smtp_port,
-        :smtp_ssl,
+        :smtp_ssl_mode,
         :smtp_enabled,
         :smtp_updated_by,
         :smtp_updated_at,
@@ -890,7 +903,7 @@ class GroupsController < ApplicationController
 
     if should_clear_smtp
       attributes[:smtp_server] = nil
-      attributes[:smtp_ssl] = false
+      attributes[:smtp_ssl_mode] = false
       attributes[:smtp_port] = nil
       attributes[:email_username] = nil
       attributes[:email_password] = nil