Per I1702c11928f8760, tests should fail when trying to make a
HTTP request, unless they have explicitely defined the desired
response.
This patch implements the same behavior for the newly introduced
createGuzzleClient() method.
Bug: T263816
Bug: T262443
Change-Id: Ie3c2efb1387ecc5bc29ff1749cae4bb33e636e9f
MockHttpTrait can be used by tests that need to simulate HTTP requests.
Bug: T262443
Needed-By: I1832cb1858ef4cf42ec34cb7fda509ce5b951c27
Needed-By: I390856b4609635cee22253071f21ce63ff716791
Needed-By: Iff24b55dfaf7a4e02a4c80aaeaf0366de5660ef1
Needed-By: Ia8213725839e4b697c4985060bc35593fea622bc
Change-Id: I8ce17da7315b87b8dd0e502e601b9ac488089456