Fix boolean arg types parsing and encoding

[valentinpalkovic]

Closes #20960

What I did

Convert string boolean type to boolean type.

How to test

1. Run a random sandbox for template, e.g. yarn task --task sandbox --start-from auto --template react-vite/default-ts
2. Open Storybook in your browser
3. Access ADDONS controls/basics/Undefined story
4. Set the boolean value
5. Refresh the page. The boolean value should be actually true or false, instead of "true" or "false"

Rationale

When the current serialization/parsing logic for URLs was implemented, we mostly relied on argTypes to be able to parse things back to the correct type. However, those types aren't always available or might be a union type (e.g. string | number) so that's insufficient. We introduced !null and !undefined and those color things in order to be able to represent those in the URL (how else could you?).
We assumed booleans would be handled via argTypes, so we did not introduce a special serialization syntax for those.

Of course, we considered the various standard serialization syntaxes, including JSON. However, JSON is actually a terrible fit for URLs because it uses quotes all over the place (which are super ugly in URLs) and simply removes undefined values as if they were never there (try JSON.stringify({ foo: undefined })). So we decided to stick with what qs provides and build a dialect on top to handle these special data types.

In this PR, we continue to use our own dialect on top of qs to support also boolean values. This solution of course isn't bug-free (the string !true will be converted into a boolean `true) We consider this as an absolute edge-case. In the future, we might revisit this decision to use JSON parsing instead (although we would sacrifice readability).

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]

[ghengeveld]

LGTM 👍