Add vertical autocomplete fixture

[nmanu1]

Add a vertical autocomplete fixture and update test suites where something is types in the search bar of a vertical page. Since no tests rely on selecting any vertical autocomplete options, the mocked response for any input returns no autocomplete options.

J=SLAP-2174 TEST=auto

Check that the fixture is used to mock the vertical autocomplete responses when expected and see that tests still pass.

[coveralls]

Coverage remained the same at 61.548% when pulling 27164ed9dff6bbba8d4838cf81878f3f816ba953 on dev/vertical-autocomplete-fixture into 4cffd50c85ff5150091280e319c054d0599d6451 on develop.