Amend TimeoutPacket to allow timeouts during an upgrade.

[DimitrisJim]

Summary

Allow packets to be timed out on a channel undergoing an upgrade.

Problem Definition

It currently isn't possible to timeout a packet due to the following condition:

ibc-go/modules/core/04-channel/keeper/timeout.go

Lines 87 to 92 in 49cdfc5

	if channel.State != types.OPEN {
	return errorsmod.Wrapf(
	types.ErrInvalidChannelState,
	"channel state is not OPEN (got %s)", channel.State.String(),
	)
	}

Spec doesn't have this condition, probably due to the initial support for optimistic sends.

Based on my understanding, this condition should match that for AcknowledgePacket which is disallowing it to timeout if channel.State != OPEN && channel.FlushStatus != FLUSHING (i.e only OPEN channels or channels in TRYUPGRADE/ACKUPGRADE that are currently flushing are actually allowed).

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For Admin Use

• Not duplicate issue
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• Appropriate contributors tagged/assigned