Fix `gettransaction` Bitcoin RPC endpoint

[brice-stacks]

The confirmations field should be a signed integer, since it goes negative when the transaction is conflicting.

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 72.81%. Comparing base (fdf1041) to head (7c2cf19). :warning: Report is 51 commits behind head on develop.

:x: Your project status has failed because the head coverage (72.81%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6749      +/-   ##
===========================================
- Coverage    77.68%   72.81%   -4.88%     
===========================================
  Files          580      580              
  Lines       360194   360229      +35     
===========================================
- Hits        279832   262315   -17517     
- Misses       80362    97914   +17552     

Files with missing lines	Coverage Δ
...-node/src/burnchains/rpc/bitcoin_rpc_client/mod.rs	94.16% <ø> (-3.12%)	:arrow_down:

... and 277 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update fdf1041...7c2cf19. Read the comment docs.

:rocket: New features to boost your workflow:

• :snowflake: Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• :package: JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions[bot]]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.