Use extension options for unordered txs

[technicallyty]

see if its possible to use the existing extension options to extend a tx as "unordered".

this has 1 main benefit:

no tx compat layer needed. currently, we have TxBody, and TxBodyCompat - the only difference here being the unordered bool and timeout_timestamp field.

because of this, special care is needed when generating transaction bytes since v50 clients won't be able to decode, due to the SDK's rejecting transaction bytes with unknown proto fields.

[technicallyty]

extension options are not signed in legacy amino.

cosmos-sdk/client/tx/aux_builder.go

Lines 222 to 233 in 39b0244

	auxBody := &txv1beta1.TxBody{
	Messages: body.Messages,
	Memo: body.Memo,
	TimeoutHeight: body.TimeoutHeight,
	TimeoutTimestamp: body.TimeoutTimestamp,
	// AuxTxBuilder has no concern with extension options, so we set them to nil.
	// This preserves pre-PR#16025 behavior where extension options were ignored, this code path:
	// https://github.com/cosmos/cosmos-sdk/blob/ac3c209326a26b46f65a6cc6f5b5ebf6beb79b38/client/tx/aux_builder.go#L193
	// https://github.com/cosmos/cosmos-sdk/blob/ac3c209326a26b46f65a6cc6f5b5ebf6beb79b38/x/auth/migrations/legacytx/stdsign.go#L49
	ExtensionOptions: nil,
	NonCriticalExtensionOptions: nil,
	}

as of now, this is leaning towards not possible.