Shared Storage: Remove Shared Storage support from DevTools

Chrome has announced that the current approach to third-party cookies
will be maintained, and adoption of the Shared Storage API has since
decreased significantly. Consequently, Shared Storage is being
deprecated and removed from Chrome as part of the Privacy Sandbox
deprecation plan. Previously, DevTools supported Shared Storage event
tracking and data introspection in the Application panel, along with
worklet target debugging in the SDK. Leaving these components in place
would result in obsolete UI elements and dead code once the web
platform API is removed.

This commit removes Shared Storage support from DevTools:
- Deletes the Shared Storage views, components, model, and tree
  elements from the Application panel (SharedStorageEventsView,
  SharedStorageItemsView, SharedStorageMetadataView, etc.).
- Removes SHARED_STORAGE_WORKLET target handling, event breakpoints,
  and instrumentation from the core SDK (Target, ChildTargetManager,
  EventBreakpointsModel, CategorizedBreakpoint, and
  ExecutionContextSelector).
- Removes associated unit tests, end-to-end tests, and build target
  references.

Removing these surfaces aligns DevTools with the web platform removal
schedule, maintains code health, and prevents developer confusion from
non-functional storage introspection tools.

Bug: 535990398,462465887
Change-Id: Ia0c5d8197e102cad86105f116a0542ff52b4b0b4
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/8155881
Reviewed-by: Connor Clark <cjamcl@chromium.org>
Reviewed-by: Danil Somsikov <dsv@chromium.org>
Commit-Queue: Cammie Smith Barnes <cammie@chromium.org>