feat(Diagnostics): split CDC and its implementation

[artemmufazalov]

Closes #2142

Stand: https://nda.ya.ru/t/GHkj9rbC7ETqAw

Motivation: fix current bugs (not working Tablets tab) and prevent further bugs connected with complex logic of merging entity and its implementation

CI Results

Test Status: ⚠️ FLAKY

📊 Full Report

Total	Passed	Failed	Flaky	Skipped
318	317	0	1	0

😟 No changes in tests. 😕

Bundle Size: 🔽

Current: 83.52 MB | Main: 83.53 MB
Diff: 0.01 MB (-0.01%)

✅ Bundle size decreased.

ℹ️ CI Information

• Test recordings for failed tests are available in the full report.
• Bundle size is measured for the entire 'dist' directory.
• 📊 indicates links to detailed reports.
• 🔺 indicates increase, 🔽 decrease, and ✅ no change in bundle size.

[Copilot]

Pull Request Overview

This PR refactors the diagnostics functionality by splitting CDC and its implementation, aiming to fix the Tablets tab bug and simplify the underlying logic. Key changes include removing multi-overview queries and related selectors, updating schema mappings for CDC stream types, and adding a new subType prop that cascades through various diagnostic components.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/store/reducers/overview/overview.ts	Removed multi-overview query and selectors for cleanup.
src/containers/Tenant/utils/schema.ts	Updated schema mappings; removed isEntityWithMergedImplementation.
src/containers/Tenant/Tenant.tsx	Added subType prop to pass along to ObjectGeneral.
src/containers/Tenant/ObjectGeneral/ObjectGeneral.tsx	Propagated subType to Diagnostics component.
src/containers/Tenant/Diagnostics/Overview/Overview.tsx	Refactored CDC stream handling using currentData from API.
src/containers/Tenant/Diagnostics/Overview/ChangefeedInfo/ChangefeedInfo.tsx	Removed topic parameter and adjusted ChangefeedInfo behavior.
src/containers/Tenant/Diagnostics/DiagnosticsPages.ts	Introduced new CDC_STREAM_IMPL_PAGES mapping.
src/containers/Tenant/Diagnostics/Diagnostics.ts	Updated diagnostics routing by including subType.
src/containers/Tenant/Diagnostics/Describe/Describe.tsx	Simplified Describe component by removing type-dependent logic.

Comments suppressed due to low confidence (2)

src/containers/Tenant/utils/schema.ts:226

• The change in mapping for EPathType.EPathTypeCdcStream from true to false alters the behavior of CDC stream handling. Please confirm that this change is intentional and aligns with the updated CDC implementation requirements.

[EPathType.EPathTypeCdcStream]: false,

src/containers/Tenant/Diagnostics/Overview/ChangefeedInfo/ChangefeedInfo.tsx:45

• Removing the topic parameter in ChangefeedInfo changes its behavior by no longer requiring separate topic data. Verify that this refactoring satisfies the intended CDC stream diagnostics and that no additional topic-related logic is needed.

if (!data) {