Add inputs to sign arg to PSBT logic

[victorkirov]

TODO: Unit testing

🔘 PR Type

What kind of change does this PR introduce?

• [x] Bugfix

📜 Background

The new PSBT logic ignored the inputs to sign arg from sats connect. It actually needs to process them in case of a multisig scenario where we cannot match the inputs witness script to the pub key.

🔄 Changes

Does this PR introduce a breaking change?

• [ ] Yes, Incompatible API changes
• [x] No, Adds functionality (backwards compatible)
• [ ] No, Bug fixes (backwards compatible)

Changes:

• The inputs to sign arg is no longer ignored

To test:

• Use this file in this branch in the sats-connect example app: https://github.com/secretkeylabs/sats-connect-example/blob/victor/aproot-example/src/components/taprootPsbt.tsx
• Try and go through the flow in that component
• The prior consolidated PSBT logic should fail while the new one should succeed

✅ Review checklist

Please ensure the following are true before merging:

• [ ] Code Style is consistent with the project guidelines.
• [ ] Code is readable and well-commented.
• [ ] No unnecessary or debugging code has been added.
• [ ] Security considerations have been taken into account.
• [ ] The change has been manually tested and works as expected.
• [ ] Breaking changes and their impacts have been considered and documented.
• [ ] Code does not introduce new technical debt or issues.

[github-actions[bot]]

Test this PR with npm i --save-exact @secretkeylabs/xverse-core@7.2.0-dcc9c2b