[omnibox][ai-mode] fieldtrial_testing_config.json

1 of the features, `kAiModeOmniboxEntryPoint`, changes the tab focus &
popup opening order of the omnibox. This CL disables the feature in some
tests that run through focusing the omnibox so they continue to pass.
Once the feature launches, we'll have to update these tests to match the
new focus order.

(cherry picked from commit d81aad568dfb9809f8e33d333cb2fab387bbb203)

Bug: 428981325, 441102004
Change-Id: I8234f9decd7d77b94cb65df7809b04093069f725
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6861711
Auto-Submit: manuk hovanesian <[email protected]>
Reviewed-by: Eshwar Stalin <[email protected]>
Commit-Queue: Justin Donnelly <[email protected]>
Reviewed-by: Devlin Cronin <[email protected]>
Cr-Original-Commit-Position: refs/heads/main@{#1506133}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6880695
Bot-Commit: Rubber Stamper <[email protected]>
Reviewed-by: Krishna Govind <[email protected]>
Owners-Override: Krishna Govind <[email protected]>
Auto-Submit: Justin Donnelly <[email protected]>
Cr-Commit-Position: refs/branch-heads/7375@{#7}
Cr-Branched-From: 3eef5210184ef83d355f189a14abd92fb7164cb6-refs/heads/main@{#1505827}

• chrome/browser/extensions/api/omnibox/omnibox_api_interactive_test.cc[diff]
• chrome/browser/ui/browser_focus_uitest.cc[diff]
• chrome/browser/ui/lens/lens_overlay_controller_browsertest.cc[diff]
• chrome/browser/ui/omnibox/omnibox_view_browsertest.cc[diff]
• chrome/browser/ui/toasts/toast_controller_interactive_ui_test.cc[diff]
• chrome/browser/ui/views/location_bar/lens_overlay_page_action_icon_view_interactive_uitest.cc[diff]
• chrome/browser/ui/views/location_bar/location_bar_view_browsertest.cc[diff]
• chrome/browser/ui/views/omnibox/omnibox_view_views_browsertest.cc[diff]
• chrome/browser/ui/views/zoom/zoom_view_interactive_ui_tests.cc[diff]
• testing/variations/fieldtrial_testing_config.json[diff]