Increase the number of blocks to keep stale messages (#945)

We just increase our block speed drastically.  As such, we need to
increase the amount of blocks to allow messages to remain stale.
This is because we have more blocks per minute.

We also don't need to check quite as often for the same reason.

Co-authored-by: Tyler Ruppert <{ID}+{username}@users.noreply.github.com>

x/consensus/module.go

@@ -164,8 +164,8 @@ func (am AppModule) EndBlock(ctx sdk.Context, _ abci.RequestEndBlock) []abci.Val
 		am.keeper.Logger(ctx).Error("error while attesting to messages", "err", err)
 	}
 
-	if ctx.BlockHeight()%10 == 0 {
-		err := am.keeper.DeleteOldMessages(ctx, 300)
+	if ctx.BlockHeight()%50 == 0 {
+		err := am.keeper.DeleteOldMessages(ctx, 1200)
 		if err != nil {
 			am.keeper.Logger(ctx).Error("error while deleting old messages", "err", err)
 		}