Restore !isCloud coverage in authTokenPriority.test.ts after the team-workspace flag retirement

Residual from the review of #14613. Non-blocking, small. #14613 replaced `flags.teamWorkspacesEnabled` with `isCloud` in `authStore.getAuthHeader()` and `getAuthToken()`. The negative test case that covered the other branch was deleted in the same push and never restored: ```ts it('skips workspace header when team_workspaces feature is disabled', async () => { ... }) ``` `src/stores/__tests__/authTokenPriority.test.ts` now has no coverage for `!isCloud` skipping the workspace header, so a regression that made the workspace-token branch unconditional would not be caught anywhere in the suite. The adaptation is close to one line: the file already hoists a mutable `mockDistributionTypes` at `:17-22` wired through `vi.mock('@/platform/distribution/types', ...)` at `:101`, so the case can be restored against the surviving `isCloud` guard instead of the retired flag. Thread: https://github.com/Comfy-Org/ComfyUI_frontend/pull/14613#discussion_r3708210823