[Extensions] Update ExtensionSettingsUIBrowserTests to manifest v2

ExtensionSettingsUIBrowserTests have been updated to manifest v2.
Remove the allowance for manifest v1 extensions.

Bug: 816679

Change-Id: Ib0d7f277f7c2d79a941c689962e84030d24fe5b7
Reviewed-on: https://chromium-review.googlesource.com/1026086
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553381}
2 files changed