Replace lib/hex with Buffer.from

[ekzyis]

Description

When converting to/from hex, we are using Buffer.from() in every other place, so this makes our code more consistent.

Checklist

Are your changes backward compatible? Please answer below:

yes

On a scale of 1-10 how well and how have you QA'd this change and any features it might affect? Please answer below:

10. Tested by comparing iv and encrypted of the previous code with the new code and saving a send wallet.

For frontend changes: Tested on mobile, light and dark mode? Please answer below:

n/a

Did you introduce any new environment variables? If so, call them out explicitly here:

no

Did you use AI for this? If so, how much did it assist you?

no

[huumn]

this is available in browsers now? that's cool, i'm pretty sure it wasn't a few years ago

[ekzyis]

No, NextJS injects polyfills and Buffer seems to be one of them even though I haven't found that specific polyfill mentioned in their docs 🤔

But I ran the code and it works