Handle errors in PSBT signing request without crashing

[yknl]

Component

Sign PSBT request

Severity

Choose one:

• Major (Unable to proceed on a journey)

Summary

When PSBT parsing throws an error, it should not crash. But instead show the error in the UI.

Reproduce steps

1. Run the sats connect example app https://github.com/secretkeylabs/sats-connect-example
2. Change the psbtBase64 param to something invalid for the sign transaction request
3. Press Sign transaction

Expected result

Nice UI showing that the PSBT was invalid and cannot be processed

Actual result

Crash

Remark

(Optional)