Prohibit untrusted proxys from specifying proxied attribution tags

Only trusted proxies should be allowed to specify tags. Also prevents
startOperationDryRun from editing the know attribution tags, as the dry
run should change no state.

Bug: 445917646
Test: atest AttributionTest
Flag: EXEMPT CVE_FIX
(cherry picked from commit 110db0acb84cbd21f9da9391ab242d141ebf390c)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:94d32dce4639ba16b321667719678d2a6b42d9c3
Merged-In: I14ab1389384fd28009edd9cceceaacdb97fb96e5
Change-Id: I14ab1389384fd28009edd9cceceaacdb97fb96e5