tutorial: Disable end credits

Closes #5543.

changelog.md

@@ -30,6 +30,8 @@
      * Adjust campaign difficulty
     * The South Guard
      * Reduce campaign difficulty
+   * Tutorial:
+     * Disabled end credits (issue #5543).
    * Under the Burning Suns:
      * Adjust campaign difficulty
  ### Editor

data/campaigns/tutorial/_main.cfg

@@ -17,6 +17,7 @@
     year="9999 AF"
     define=TUTORIAL
     first_scenario=tutorial
+    end_credits=no
     description= _ "Learn the basics of Wesnoth gameplay with a tutorial. Recommended for first time players."
     [difficulty]
         # The difficulty-select dialog won’t be shown to the player, as there's