Move chainID strictness check from 02-client UpgradeChain proposal handler to ValidateBasic

[colin-axner]

Summary

Pre-requirement:

• Migrate governance proposals from v1beta1 to v1 #1282

Move the switch case added in #1309 to a check in message ValidateBasic on a proposal submission for UpgradeChain (so that we perform this check long before the proposal would pass). We must migrate from x/gov v1beta1 to x/gov v1 first.

The current behaviour will perform the check after the proposal passes, but ideally we would immediately reject any proposal which uses a bad chainID to upgrade to. v1beta1 does not support this as we need the context to determine if the next chainID makes sense.

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For Admin Use

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