FEATURE: One-click chat reaction settings (#32150)

Adds a one-click chat reactions setting to the chat preferences page
where members can determine what one-click reactions are shown in chat.

- Frequent: This will be the default setting. (Automatically set based
on most used chat reactions)
- Custom: Members can choose up to three reactions they want to see in
their one-click chat/DM reactions menu. Defaults are `❤️`, `👍` ,
and `😄`.


![image](https://github.com/user-attachments/assets/8913db0e-d6ec-4347-ad91-2329206b127c)

This pull request is essentially the work of @dsims in
https://github.com/discourse/discourse/pull/31761

---------

Co-authored-by: dsims <1041068+dsims@users.noreply.github.com>

plugins/chat/db/migrate/20250307185912_add_chat_quick_reaction_preferences.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+class AddChatQuickReactionPreferences < ActiveRecord::Migration[7.2]
+  def change
+    add_column :user_options, :chat_quick_reaction_type, :integer, default: 0, null: false
+    add_column :user_options, :chat_quick_reactions_custom, :string
+  end
+end