feat: Update the design for dashboard_apps (#9840)

This PR migrates the dashboard apps page to the new layout and includes
the following updates:

- Create a compact design for the back button
- Add a back button to the settings header
- Reduce letter-spacing on the description
- Fix mobile styles
- Migrate the layout of dashboard apps/index to new layouts


Note: I've moved all feature help URLs from features.yml to the frontend. This change prevents features.yml from becoming bloated due to frontend modifications.

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

app/javascript/dashboard/i18n/locale/en/integrations.json

@@ -172,6 +172,7 @@
       "HEADER_BTN_TXT": "Add a new dashboard app",
       "SIDEBAR_TXT": "<p><b>Dashboard Apps</b></p><p>Dashboard Apps allow organizations to embed an application inside the Chatwoot dashboard to provide the context for customer support agents. This feature allows you to create an application independently and embed that inside the dashboard to provide user information, their orders, or their previous payment history.</p><p>When you embed your application using the dashboard in Chatwoot, your application will get the context of the conversation and contact as a window event. Implement a listener for the message event on your page to receive the context.</p><p>To add a new dashboard app, click on the button 'Add a new dashboard app'.</p>",
       "DESCRIPTION": "Dashboard Apps allow organizations to embed an application inside the dashboard to provide the context for customer support agents. This feature allows you to create an application independently and embed that to provide user information, their orders, or their previous payment history.",
+      "LEARN_MORE": "Learn more about Dashboard Apps",
       "LIST": {
         "404": "There are no dashboard apps configured on this account yet",
         "LOADING": "Fetching dashboard apps...",