Add boundary tests for IBC channel parameter validation

[modernzju]

Summary

Adds unit coverage for ValidateChannelParams to document and verify the IBC channel sequence boundary behavior.

The new tests cover:

• channel-0
• the maximum allowed uint32 channel sequence
• a channel sequence above uint32
• an invalid channel ID format

This is a test-only change and does not modify runtime behavior.

Testing

• gofmt
• git diff --check

I attempted to run:

go test -mod=readonly -tags='ledger test_ledger_mock' ./x/wasm -run '^TestValidateChannelParams$' -count=1