browsertest: correct spelling of AmbientModePage

BUG=none
TEST=browser_tests --gtest_filter="OSSettingsAmbientModePageV3Test.All"

Change-Id: Ia097fb823b0e5f828444befe64b50b8e677c71cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2347344Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Jeffrey Young <cowmoo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796875}

chrome/test/data/webui/settings/chromeos/os_settings_v3_browsertest.js

@@ -37,7 +37,7 @@ var OSSettingsV3BrowserTest = class extends PolymerTest {
   }
 };
 
-[['AmbientModePpage', 'ambient_mode_page_test.m.js'],
+[['AmbientModePage', 'ambient_mode_page_test.m.js'],
  ['BluetoothPage', 'bluetooth_page_tests.m.js'],
  ['DateTimePage', 'date_time_page_tests.m.js'],
  ['InputMethodOptionPage', 'input_method_options_page_test.m.js'],