refactor(welcome): Remove disable_goodbye error handler

Removes the dedicated error handler for the `disable_goodbye` command.
This allows for more centralized or general error handling to take over.
Adds a log message when the WelcomeCog is successfully loaded.

cogs/welcome_cog.py

@@ -337,8 +337,6 @@ class WelcomeCog(commands.Cog):
             await ctx.send("Failed to disable goodbye messages. Check logs.")
             log.error(f"Failed to disable goodbye settings for guild {guild_id}")
 
-    # Error Handling for this Cog
-    @disable_goodbye.error
     # --- Test Commands ---
     @commands.group(
         name="testmessage",
@@ -473,3 +471,4 @@ async def setup(bot: commands.Bot):
     welcome_cog = WelcomeCog(bot)
     await bot.add_cog(welcome_cog)
     log.info("WelcomeCog loaded.")
+