For `toolbar` bottom component, let users add a search bar

[pylapp]

Description

Description

As a developer user,
I want to add a search bar in my bottom toolbar,
So that my final users will be able to search things in my app

Below a screenshot of the native search bar in bottom toolbar for Apple Messages app

Context

Today the toolbar bottom component allows users to add items like buttons with several stylings.
However it is quite common to have with iOS 26 and Liquid Glass a toolbar containing a search bar, a bit like the tab bar with a tab applying the search rule.

Motivation & Context

Allows users to have a native search bar

Types of change

• Add new component
• Update existing component

Checklist for Core Team

• Tokens have been updated
• Documentations have been updated
• Unit tests have been updated
• UI tests have been updated
• Design System Toolbox has been updated
• Retrocompatibility has been checked, or broken API have been flagged as deprecated with a workaround