imp(ibc-client): rm `TryFrom<Error = ClientError>` restriction

[rnbguy]

Closes: #1203

Description

• Removes Error = ClientError in TryFrom implementations. This prevented TryFrom<Error = Infallible> from being reused.
• Reverses the direction of Convertible - so that ClientStateDecoder and ConsensusStateDecoder can be replaced by Convertible<Any>.

---

PR author checklist:

• [ ] Added changelog entry, using unclog.
• [ ] Added tests.
• [ ] Linked to GitHub issue.
• [ ] Updated code comments and documentation (e.g., docs/).
• [ ] Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• [ ] Reviewed Files changed in the GitHub PR explorer.
• [ ] Manually tested (in case integration/unit/mock tests are absent).

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.55172% with 2 lines in your changes are missing coverage. Please review.

:exclamation: No coverage uploaded for pull request base (main@ed4f8cd). Click here to learn what that means.

Files	Patch %	Lines
...nts/ics07-tendermint/src/client_state/execution.rs	83.33%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1204 +/- ## ======================================= Coverage ? 64.43% ======================================= Files ? 229 Lines ? 22041 Branches ? 0 ======================================= Hits ? 14202 Misses ? 7839 Partials ? 0 ```

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[rnbguy]

Looks like, with this - we can remove types::ClientState and types::ConsensusState usage in ICS-07 and use client_state::ClientState and consensus_state::ConsensusState directly.

This will reduce confusion for downstream users.