test: cover hub.component sidebar gating and routerLinks

[Ma77Ball]

What changes were proposed in this PR?

• Replace the hub.component.spec.ts smoke test with nine tests covering default-input render, GuiConfigService injection, per-flag sidebarTabs.*_enabled gating, all-enabled rendering, exclusion of disabled tabs, routerLink bindings to the three routing constants, and isLogin input passthrough.
• Wrap HubComponent in a test host <ul nz-menu> so nz-menu-item directives resolve their DI tokens the same way they do under the dashboard at runtime.
• Read routerLink via the directive's routerLinkInput signal since the routerLink input is a write-only setter and ng-reflect-router-link is not populated in the Vitest environment.

Any related issues, documentation, or discussions?

Closes: #5224

How was this PR tested?

• yarn test --include='src/app/hub/component/hub.component.spec.ts': 9 passed, 0 failed.
• yarn format:fix: 506 files unchanged.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.7 in compliance with ASF

[codecov-commenter]

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