fix: Adjust the FPI tutorial to 0.12

[WiktorStarczewski]

Adjusts the FPI tutorial to 0.12.
Mirrors 0xMiden/miden-docs#98.

[Keinberger]

Please update the corresponding .md file in the docs folder too!

[Keinberger]

Let's delete the redundant console.log statements, i.e. among others "POST", "HERE", "PRE", etc...

I also don't think we need to console log the FPI script code.

[Keinberger]

Also, please make sure that other parts of the .md file are updated accordingly. For instance, the "Key WebClient Concepts for FPI" section needs to be updated with the new account component library syntax.

In regards to that point, please also review the .md files of the other web tutorials (even the ones that were already merged), in case there are any changes to the content of those md files that are still missing and need to be updated.

[Keinberger]

Made some more fixes to this PR, as can be seen by the commits above (removed redundant debugging messages, fixed the markdown tutorial instructions, etc...).

@WiktorStarczewski Please review the latest changes.

NOTE: Furthermore, we have an issue with our CI workflow that runs prettier: As of now, it uses the root prettier config. However, for the typescript markdown code, we want to use different linter settings than the rust code. That means we'll have to find a way to reconfigure the workflow to use different prettier settings for the Rust code and the Typescript code