Revert "WebUI Settings: Navigate away from Site Details with empty site"

This reverts commit d9a97a18.

Reason for revert: 
CrSettingsSiteDetailsTest.SiteDetails fails
https://ci.chromium.org/p/chromium/builders/ci/mac-arm64-rel-tests

Original change's description:
> WebUI Settings: Navigate away from Site Details with empty site
>
> To prevent users interacting with the Site Details page without having
> a site set (which can crash Chrome if the user attempts to reset
> permissions) the page is configured to navigate up a level if no site
> is provided.
>
> The user can only reach this page without a site by manually typing it
> into the address bar.
>
> Bug: 1241396
> Change-Id: If48b105e60ee13c08ee894ccab58819954066a25
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3114456


> Reviewed-by: Sean Harrison <harrisonsean@chromium.org>
> Commit-Queue: Theodore Olsauskas-Warren <sauski@google.com>
> Cr-Commit-Position: refs/heads/main@{#915102}

Bug: 1241396
Change-Id: I02f5daf05cb9bebb6711047daab6e4673669d736
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3118025


Auto-Submit: Michael Ershov <miersh@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Theodore Olsauskas-Warren <sauski@google.com>
Commit-Queue: Michael Ershov <miersh@google.com>
Reviewed-by: Theodore Olsauskas-Warren <sauski@google.com>
Owners-Override: Michael Ershov <miersh@google.com>
Cr-Commit-Position: refs/heads/main@{#915150}