DsePreload2: Consume pipeline if it is likely used

In DSE v1, `SearchPrefetchRequest` is consumed when a non-prerender
navigation claim to use it.

Before this patch, in DSE v2, prefetch was reusable.

This CL makes DSE v1/v2 aligned; consuming preloads if it is used.

See also discussion
https://docs.google.com/document/d/1NjxwlOEoBwpXojG13M85XtS8nH-S4uc0F6VOrlwIAXE/edit?pli=1&tab=t.0#heading=h.5qv0ome418fo

Fixed: 423556625
Change-Id: Ibb304c0ef1ff637e9d7c7a6115fb91fb19cc503d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6626729
Commit-Queue: Ken Okada <kenoss@chromium.org>
Reviewed-by: Lingqi Chi <lingqi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1474226}