fix(live): Firefox: disable the initial configuration workflow (#1573)

## Problem

In SLFO the Firefox shows the welcome screen at the first start instead
of the Agama page.


![Agama-Firefox-SLE](https://github.com/user-attachments/assets/df2abd2f-4683-4066-99cc-e90b0212c758)


## Solution

- Disable the initial welcome screen in the default Firefox profile

## Testing

- With this option the welcome screen is skipped

live/root/root/.mozilla/firefox/profile/user.js.template

@@ -5,6 +5,9 @@ user_pref("signon.management.page.breach-alerts.enabled", false);
 user_pref("signon.rememberSignons", false);
 user_pref("signon.generation.enabled", false);
 
+// disable the initial configuration workflow
+user_pref("browser.aboutwelcome.enabled", false);
+
 // start always in the custom homepage
 user_pref("browser.startup.page", 1);
 // custom homepage: the value is expected to be replaced with the login URL by the startup script

live/src/agama-installer.changes

@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Tue Sep  3 14:50:58 UTC 2024 - Ladislav Slezák <lslezak@suse.com>
+
+- Firefox: disable the initial configuration workflow
+  (gh#openSUSE/agama#1573)
+
 -------------------------------------------------------------------
 Fri Aug 30 13:05:53 UTC 2024 - Thomas Blume <Thomas.Blume@suse.com>