[FRAME] fix: Do not emit Issued { amount: 0 } event

[ShoyuVanilla]

closes #5942

Couldn't find any emissions of Event::Issued without amount check other than in this PR.

Currently, we have;

polkadot-sdk/substrate/frame/balances/src/impl_currency.rs

Lines 212 to 220 in 4bda956

	impl<T: Config<I>, I: 'static> Drop for PositiveImbalance<T, I> {
	/// Basic drop handler will just square up the total issuance.
	fn drop(&mut self) {
	if !self.0.is_zero() {
	<super::TotalIssuance<T, I>>::mutate(|v| *v = v.saturating_add(self.0));
	Pallet::<T, I>::deposit_event(Event::<T, I>::Issued { amount: self.0 });
	}
	}
	}

and

polkadot-sdk/substrate/frame/balances/src/impl_currency.rs

Lines 293 to 306 in 4bda956

	fn issue(mut amount: Self::Balance) -> Self::NegativeImbalance {
	if amount.is_zero() {
	return NegativeImbalance::zero()
	}
	<TotalIssuance<T, I>>::mutate(|issued| {
	*issued = issued.checked_add(&amount).unwrap_or_else(|| {
	amount = Self::Balance::max_value() - *issued;
	Self::Balance::max_value()
	})
	});
	Pallet::<T, I>::deposit_event(Event::<T, I>::Issued { amount });
	NegativeImbalance::new(amount)
	}

[ggwpez]

Looks good, thanks! Please add a minimal prdoc so that it shows up correctly in the CHANGELOG: https://github.com/paritytech/polkadot-sdk/blob/master/docs/contributor/prdoc.md

[ShoyuVanilla]

Looks good, thanks! Please add a minimal prdoc so that it shows up correctly in the CHANGELOG: https://github.com/paritytech/polkadot-sdk/blob/master/docs/contributor/prdoc.md

Thanks! I'll add it soon

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