feat!: allow the chain id to be updated if the chain has not yet launched

[insumity]

Description

Problem
Some consumer chains would like to reserve a consumerId but without yet knowing their chainId. Currently, to reserve the consumerId, you have to send a MsgRegisterConsumer that also gets the chainId as a parameter and chainId cannot later be changed.

Solution
Introduce new_chain_id in MsgUpdateConsumer so that a consumer chain can update its chainId after registration. Note that the chainId can only be updated before the consumer chain launches.

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Author Checklist

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I have...

• Included the correct type prefix in the PR title
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I have...

• confirmed the correct type prefix in the PR title
• confirmed ! the type prefix if the change is state-machine breaking
• confirmed this PR does not introduce changes requiring state migrations, OR confirmed migration code has been added to consumer and/or provider modules
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage

[mpoke]

In general, LGTM. Just make sure to correctly validate the new chain ID.

[MSalopek]

LGTM