Install Olivero and Claro in the minimal recipe

Problem/Motivation

Until recently, core required an install profile to run at all. Install profiles are now optional, but not in the UI installer - you have to pick one.

After #2818085: [meta] Recipe downloads from the installer. → and existing core install profiles as recipes, we'll be able to deprecate install profiles or at least make them fully optional, and let people install recipes instead.

Once we have that, we're likely to still want a 'skip all this and let me start from scratch' option - where you would get to the end of the installer, and be able to install extensions.

However, the minimal install profile is not really meant to be used by people, it more something you can set for the install profile setting, then immediately install your site from config after that.

To make the 'skip' option more usable, I think we should install claro and olivero - it's much easier to switch and uninstall a theme than uninstall modules, so those won't really undermine the 'minimal' nature of the recipe, but it'll mean people can actually find their way round without things looking completely broken (like stark intentionally does).

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet