Hermes ft-transfer: Verify open channel before sending message

[adizere]

Closes: #960

Description

Using a non-Open channel will result in an explicit error. For example, channel channel-3 on chain ibc-0 is in state Init.

$ hermes --json tx raw ft-transfer ibc-1 ibc-0 transfer channel-3 10000 -o 1000 -n 2

{"result":"the requested port/channel ('transfer'/'channel-3') on chain id 'ibc-0' is in state 'INIT'; expected 'open' state","status":"error"}

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For contributor use:

• Updated the Unreleased section of CHANGELOG.md with the issue.
• If applicable: Unit tests written, added test to CI.
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Updated relevant documentation (docs/) and code comments.
• Re-reviewed Files changed in the Github PR explorer.