ATLAS-5294: ATLAS UI: Shared component library tests

[pawarprasad123]

What changes were proposed in this pull request?

Add unit tests for shared React components.

This PR tests reusable UI (forms, tables, query builder, search, show-more, etc.). These components are imported by many views; tests here prevent regressions across the whole app.

This PR covers primary navigation and high-traffic surfaces: home/overview charts, app chrome (header/layout), lineage entry, sidebar trees, saved filters, search results, and server/entity statistics views.

What changes do

• Verify rendering, user events, accessibility-oriented queries, and edge cases (empty data, disabled states) in isolation with mocks for Redux/router when needed.

• Reduce duplicate debugging: a bug in TableLayout or QuickSearch would otherwise appear as failures in many unrelated feature tests.

• DashboardOverview tests: Charts and cards (e.g. entity types, Kafka summary, latest entities, message consumption) with Recharts/MUI mocked where needed.

• Layout / Lineage tests: Shell behavior users see on almost every route.

• SideBar / Import tests: Tree navigation and glossary import dropzone flows.

• SearchResult / SaveFilters tests: Discovery and saved-query UX.

• Statistics tests: Metrics screens and graph tooltips.

Why these files are used

• Components are the main building blocks; testing them directly gives high leverage and stable snapshots of UI behavior.
• These areas are user-visible and cross-cutting; regressions affect many personas (data stewards, admins). Tests lock wiring between routers, mocks, and data props.

How was this patch tested?

Manual test