feat(ui5-shellbar) support self-collapsible search

[dobrinyonkov]

This PR updates the ShellBar search functionality to support two separate collapse modes for search fields.

Changes

Dual Mode Support:
Allows self-collapsible search with an internal toggle and collapsed property or fully custom search with its own button.

Syncing Mechanism:
The two collapse mechanisms are now synchronized using the showSearchField getter/setter instead of a combined property.

Customization Options:
New properties hideSearchButton and disableAutoSearchField enable further customization of custom search fields.

Accessibility Improvements:
Roles and labels are correctly set for the content items container.

New Features:
A new search-field-toggle event is fired when the search field is toggled by internal rules, and a new getter searchButtonRef is available for managing focus on the search button.

[Copilot]

Copilot reviewed 3 out of 5 changed files in this pull request and generated 1 comment.

Files not reviewed (2)

• packages/fiori/src/themes/ShellBar.css: Language not supported
• packages/fiori/test/pages/ShellBar_evolution.html: Language not supported

Comments suppressed due to low confidence (2)

packages/fiori/src/ShellBar.ts:1507

• The component now queries for '.ui5-shellbar-search-toggle' for the search button. Please ensure all related selectors and references (including in tests) are updated consistently.

const searchToggle = this.shadowRoot!.querySelector<HTMLElement>(".ui5-shellbar-search-toggle");

packages/fiori/cypress/specs/ShellBar.cy.tsx:402

• The tests still reference '.ui5-shellbar-search-button' while the component now uses '.ui5-shellbar-search-toggle'. Please update the test selectors to match the new class names.

.find(".ui5-shellbar-search-button")