Shared Storage: Enable selectURL limits by default

We enable the entropy bit budgets for `sharedStorage.selectURL()` by
default. Of course, whether or not these limits are enabled is moot,
if `sharedStorage` is itself disabled.

Bug: 1429680,1218540
Change-Id: Ide9464ddb8267367d2047eb780de6650fbcd6e3e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4552657


Commit-Queue: Cammie Smith Barnes <cammie@chromium.org>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1147619}