refactor: use SIGHASH_ALL explicitly

[djordon]

Description

This was discussed in #782, and came up as part of #798.

Changes

• Explicitly use TapSighashType::All, which maps to SIGHASH_ALL. This makes the sighash type explicit, which appears to increase the transaction size by at least one byte.

Before we used TapSighashType::Default, which is TapSighashType::All already. But I have a preference for making the sighash type explicit, and unfortunately this preference has a cost of increasing the transaction size by one byte. Bitcoin usually doesn't change that much and changing the default here seems like a big change so maybe we can rely on the default behavior. If someone else has an opinion here, let me know.

Testing Information

This is just a refactor, if tests pass then we're good.

Checklist:

• I have performed a self-review of my code

[cylewitruk]

Looks fine 👍