* feat: api: sanity check the "to" address of outgoing messages
If the "to" address of an outgoing message is a _delegated_ address,
verify that it maps to a valid Ethereum address. This isn't a consensus
critical change, but it'll help prevent client-side address conversion
libraries from directing messages into oblivion (e.g., by
mis-translating `0xff0000....` addresses into `f410f...` addresses
instead of `f0...` addresses.
* tests for invalid delegated addresses
* fix lint
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Co-authored-by: aarshkshah1992 <aarshkshah1992@gmail.com>
