feat: Adds internal support for markdown in Telegram outgoing messages (#8640)

This PR adds support for Markdown in the telegram API for send message. The dashboard uses commonmark syntax for markdown but telegram is using MarkdownV2.
More info - https://core.telegram.org/bots/api#markdownv2-style

Adds support for bold - *bold*, _italic text_, __underline__, ~strikethrough~

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/models/channel/telegram.rb

@@ -149,12 +149,29 @@ class Channel::Telegram < ApplicationRecord
                   })
   end
 
+  def convert_markdown_to_telegram(text)
+    # Convert bold - double asterisks to single asterisk in Telegram
+    text.gsub!(/\*\*(.*?)\*\*/, '*\1*')
+
+    # Convert italics - single underscore (same in both CommonMark and Telegram)
+    # No conversion needed for italics as both use _text_
+
+    # Convert underline - not typically used in CommonMark, so we'll leave it as is
+
+    # Convert strikethrough - double tilde to single tilde in Telegram
+    text.gsub!(/~~(.*?)~~/, '~\1~')
+
+    text
+  end
+
   def message_request(chat_id, text, reply_markup = nil, reply_to_message_id = nil)
+    text_to_md = convert_markdown_to_telegram(text)
     HTTParty.post("#{telegram_api_url}/sendMessage",
                   body: {
                     chat_id: chat_id,
-                    text: text,
+                    text: text_to_md,
                     reply_markup: reply_markup,
+                    parse_mode: 'MarkdownV2',
                     reply_to_message_id: reply_to_message_id
                   })
   end

spec/models/channel/telegram_spec.rb

@@ -10,7 +10,24 @@ RSpec.describe Channel::Telegram do
 
       stub_request(:post, "https://api.telegram.org/bot#{telegram_channel.bot_token}/sendMessage")
         .with(
-          body: 'chat_id=123&text=test&reply_markup=&reply_to_message_id='
+          body: 'chat_id=123&text=test&reply_markup=&parse_mode=MarkdownV2&reply_to_message_id='
+        )
+        .to_return(
+          status: 200,
+          body: { result: { message_id: 'telegram_123' } }.to_json,
+          headers: { 'Content-Type' => 'application/json' }
+        )
+
+      expect(telegram_channel.send_message_on_telegram(message)).to eq('telegram_123')
+    end
+
+    it 'send message with markdown converted to telegram markdown' do
+      message = create(:message, message_type: :outgoing, content: '**test** ~~test~~ *test* ~test~',
+                                 conversation: create(:conversation, inbox: telegram_channel.inbox, additional_attributes: { 'chat_id' => '123' }))
+
+      stub_request(:post, "https://api.telegram.org/bot#{telegram_channel.bot_token}/sendMessage")
+        .with(
+          body: "chat_id=123&text=#{ERB::Util.url_encode('*test* ~test~ *test* ~test~')}&reply_markup=&parse_mode=MarkdownV2&reply_to_message_id="
         )
         .to_return(
           status: 200,
@@ -32,7 +49,7 @@ RSpec.describe Channel::Telegram do
         .with(
           body: 'chat_id=123&text=test' \
                 '&reply_markup=%7B%22one_time_keyboard%22%3Atrue%2C%22inline_keyboard%22%3A%5B%5B%7B%22text%22%3A%22test%22%2C%22' \
-                'callback_data%22%3A%22test%22%7D%5D%5D%7D&reply_to_message_id='
+                'callback_data%22%3A%22test%22%7D%5D%5D%7D&parse_mode=MarkdownV2&reply_to_message_id='
         )
         .to_return(
           status: 200,
@@ -49,7 +66,7 @@ RSpec.describe Channel::Telegram do
 
       stub_request(:post, "https://api.telegram.org/bot#{telegram_channel.bot_token}/sendMessage")
         .with(
-          body: 'chat_id=123&text=test&reply_markup=&reply_to_message_id='
+          body: 'chat_id=123&text=test&reply_markup=&parse_mode=MarkdownV2&reply_to_message_id='
         )
         .to_return(
           status: 403,