- Create useDialogIds hook to eliminate duplicated useInstanceId calls
- Replace duplicated accessibility ID generation in LinkUIBlockInserter and UnforwardedLinkUI
- Maintain correct component parameters (LinkControl vs LinkUI) for proper ID generation
- Standardize dialog accessibility ID pattern across components
- Export hook for potential reuse in other components
This is the second phase of LinkUI duplication cleanup as discussed in PR #71163 follow-ups.

- Create shared DialogWrapper component that handles all dialog concerns internally
- Eliminate useDialogIds hook by inlining useInstanceId calls directly in DialogWrapper
- Derive component, componentName, and backButtonClassName from className prop
- Move useFocusOnMount logic inside DialogWrapper for complete encapsulation
- Replace duplicated dialog structures in LinkUIBlockInserter and LinkUIPageCreator
- Fix useDialogIds reference error in main LinkUI component
- Maintain all existing CSS styling and accessibility features
- Fix nested ternary linting error with if/else statements
This completes the major refactoring of LinkUI duplication cleanup as discussed in PR #71163 follow-ups.

…e BackButton
- Extract LinkUIBlockInserter component to block-inserter.js for consistency with page-creator.js
- Consolidate BackButton component into dialog-wrapper.js since it's only used there
- Fix import issues with privateApis in block-inserter.js
- Remove separate back-button.js file to reduce file count
- Clean up unused imports in link-ui.js after component extraction
- Fix JSDoc alignment in block-inserter.js
- Maintain all existing functionality while improving file organization
This completes the component extraction phase of the LinkUI duplication cleanup.

Use DialogWrapper as the component for useInstanceId instead of deriving
it from className. This removes unnecessary complexity and unused imports.