feat: disable consumer chain creation

[dasanchez]

Description

Adds an antehandler to reject MsgCreateConsumer messages.

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[dasanchez]

Interchaintest run: https://github.com/cosmos/gaia/actions/runs/21684845181

[fastfadingviolets]

Looks good to me, really just the q around ICA/Wasm.