[Omnibox] Update field trial config to encompass both experiments

Add AiModeSpaceDoesNotActivate to field trial config.

Bug: 509543743
Change-Id: Ia75ea9656a38b6a42b5b801858a72b7ed5a03155
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7831713
Commit-Queue: Marlon Facey <mfacey@chromium.org>
Reviewed-by: Aviv Kiss <avivkiss@google.com>
Cr-Commit-Position: refs/heads/main@{#1628029}
NOKEYCHECK=True
GitOrigin-RevId: 42c1a3f809d9a77cf88483763527261145b15794