fix: remove array.at usage as not supported in Native

[victorkirov]

🔘 PR Type

What kind of change does this PR introduce?

• Bugfix

📜 Background

Array.at was used in a function, but that syntax is not supported in React Native. This PR changes to using the alternative syntax.

🔄 Changes

Does this PR introduce a breaking change?

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

Impact:
The getOrdinalIdFromUtxo was failing in the mobile app. This is used in BTC recovery, which is currently not working as a result.

✅ 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]

Test this PR with npm i @secretkeylabs/[email protected]