feat: Add delreward command.

plugin/campaign.py

@@ -85,12 +85,27 @@ class RewardCampaign:
             await reward.update(**kwargs)
             await self.try_to_log_reward(reward)
 
+    async def delete_reward(self, rewardid: int):
+        reward = await EarnedReward.fetch(rewardid)
+        if reward is None:
+            raise ValueError("Reward doesn't exist")
+        await self.try_to_unlog_reward(reward)
+        await reward.delete()
+
     async def get_rewards(self) -> list[EarnedReward]:
         rows = await EarnedReward.fetch_where(
             campaign_id=self.row.campaign_id
         ).order_by("earned_at", direction=ORDER.ASC)
         return rows
 
+    async def try_to_unlog_reward(self, reward: EarnedReward):
+        import discord 
+        try:
+            if self.webhook and reward.log_messageid:
+                await self.webhook.delete_message(reward.log_messageid)
+        except discord.HTTPException:
+            pass
+
     async def try_to_log_reward(self, reward: EarnedReward):
         import discord