refactor: reuse RoleBadge component in WorkspaceSwitcherPopover

## Summary

The `RoleBadge` component was introduced in #10486 as part of decomposing `MembersPanelContent.vue`. An identical inline badge exists in `WorkspaceSwitcherPopover.vue` (around line 51) with matching styles (`rounded-full bg-base-foreground px-1 py-0.5 text-2xs font-bold ...`) that should be replaced with the new `RoleBadge` component to complete the decomposition cycle and avoid style drift.

## Task

- Replace the inline badge span in `WorkspaceSwitcherPopover.vue` with the `` component introduced in #10486.
- Verify visual parity after the substitution.

## Context

- Identified in PR: https://github.com/Comfy-Org/ComfyUI_frontend/pull/10486
- Discussion: https://github.com/Comfy-Org/ComfyUI_frontend/pull/10486#discussion_r3048594317
- Requested by: @christian-byrne

┆Issue is synchronized with this [Notion page](https://www.notion.so/Issue-10971-refactor-reuse-RoleBadge-component-in-WorkspaceSwitcherPopover-33c6d73d365081f9b534eab5beca344c) by [Unito](https://www.unito.io)