feat: make icon optional in WorkSideMenuGroup and WorkSideMenuItem

[Copilot]

WorkSideMenuGroup always rendered a leading icon, reserving space for it even when none was needed — requiring shadow DOM workarounds to hide it. WorkSideMenuItem had the same issue: the goa-icon element was always mounted even with an empty icon prop.

Before (the change)

• WorkSideMenuGroup.icon was required; always rendered a goa-icon in the summary header
• WorkSideMenuItem always mounted a goa-icon element even when icon="", consuming layout space

After (the change)

• WorkSideMenuGroup — icon is now optional across all three frameworks. The leading goa-icon is only rendered when icon is provided; no space is reserved when omitted.
• WorkSideMenuItem — goa-icon is conditionally rendered via {#if icon}, consistent with the existing optional prop contract.

<!-- WorkSideMenuGroup with no icon: clean text-only header -->
<goa-work-side-menu-group heading="Content layout" />

<!-- WorkSideMenuGroup with icon: unchanged behavior -->
<goa-work-side-menu-group heading="Dashboard" icon="home" />

React / Angular: icon prop changed from required to optional in both wrappers (GoabWorkSideMenuGroupProps, @Input() icon?: GoabIconType).

Make sure that you've checked the boxes below before you submit the PR

• I have read and followed the setup steps
• I have created necessary unit tests
• I have tested the functionality in both React and Angular.

Steps needed to test

1. Render WorkSideMenuGroup without the icon prop — confirm no icon element is mounted and heading text is flush left with no reserved icon gap.
2. Render WorkSideMenuGroup with icon="star" — confirm existing icon behavior is unchanged.
3. Render WorkSideMenuItem without icon — confirm no icon element is mounted.
4. Render WorkSideMenuItem with icon="star" — confirm icon renders as before.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add optional icon to WorkSideMenuGroup</issue_title>
<issue_description>## Description

WorkSideMenuGroup always renders a leading icon in the group header. There's no way to hide it or make it optional. When used without an icon, the component still reserves space for one, requiring shadow DOM workarounds to hide it and fix alignment.

Use case

The docs website uses WorkSideMenuGroup for nav categories (Components: Content layout, Feedback and alerts, etc.) and Get Started groups (Designers, Developers). These groups don't need icons, just text headers.

Expected behavior

WorkSideMenuGroup should support rendering without an icon. Either:

• Make the icon prop optional (no icon rendered when omitted)
  • No space reserved for icon if not provided

Current workaround

docs/src/components/nav/useGroupShadowDomFixes.ts injects styles into shadow DOM to hide the icon and adjust padding/margins.</issue_description>

<agent_instructions>The icon should be optional both for WorkSideMenuGroup.svelte and WorkSideMenuItem.svelte. The optional property should be for the respective React and Angular wrappers as well.

Here's a list of files to review:
libs/web-components/src/components/work-side-menu/WorkSideMenuGroup.svelte
libs/angular-components/src/experimental/work-side-menu-group/work-side-menu-group.ts
libs/react-components/src/experimental/work-side-menu-group/work-side-menu-group.tsx
libs/web-components/src/components/work-side-menu/WorkSideMenuItem.svelte
libs/angular-components/src/experimental/work-side-menu-item/work-side-menu-item.ts
libs/react-components/src/experimental/work-side-menu-item/work-side-menu-item.tsx</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Add optional icon to WorkSideMenuGroup #3544

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[bdfranck]

Here was my process:

1. Asked GitHub Copilot to create the initial PR
2. Tweaked the results
3. Asked Copilot to create the PR test pages
4. Squashed the commits

[bdfranck]

I've rebased this commit against the latest dev and resolved the merge conflicts.

[twjeffery]

@bdfranck Approved, looks good to me. I added a test page as well, feel free to squash that in.