Change FAB asset compilation from yarn to pnpm

[jscheffl]

As a follow-iup of #56456 I'd like to alos remove static compiled assets from repo... and in order to get it streamlined as a first step would propose to switch from yarn to pnpm in fab assets - then all in the repo is consistently using pnpm.

Alongside - as of switching package manager, upgrading all dependencies.

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[jscheffl]

No backport needed in my view

[potiuk]

Indeed.