Remove killswitch AutofillPreferProvisionalFormWhenFormlessFormIsRemoved

Bug: 41490350
Change-Id: I0b78ef011389540e1359fd2fdefb484b957867db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5419113


Reviewed-by: Christoph Schwering <schwering@google.com>
Commit-Queue: Jihad Hanna <jihadghanna@google.com>
Cr-Commit-Position: refs/heads/main@{#1281832}