Fix: Refund failed FT deposits

[jbencin]

Description

If a fungible token deposit onto a subnet fails, create a withdrawal transaction to allow the user to withdraw it from the contract

Applicable issues

• fixes #146

Additional info (benefits, drawbacks, caveats)

There is no attempt here to handle the case of a partial success (for example, a user deposits 50 tokens and only 20 appear on the subnet). This shouldn't happen, and if it does I would think it indicates a problem with the Clarity contract.

Should I move make_withdrawal_event() out of blocks.rs and into clarity_vm/withrdawal.rs?

Also including a couple minor fixes, see commit messages for details.

Checklist

• [x] Test coverage for new or modified code paths
• [ ] Changelog is updated
• [ ] Required documentation changes (e.g., docs/rpc/openapi.yaml and rpc-endpoints.md for v2 endpoints, event-dispatcher.md for new events)
• [ ] New clarity functions have corresponding PR in clarity-benchmarking repo
• [ ] New integration test(s) added to bitcoin-tests.yml

[codecov[bot]]

Codecov Report

Merging #253 (8369a9e) into master (a762f8f) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 8369a9e differs from pull request most recent head b32b7eb. Consider uploading reports for the commit b32b7eb to get more accurate results

@@           Coverage Diff           @@
##           master     #253   +/-   ##
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  Coverage   93.47%   93.47%           
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  Files           6        6           
  Lines         337      337           
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  Hits          315      315           
  Misses         22       22           

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[jbencin]

Just made all the changes requested, except removing the TODO, which I'll do as part of #256