Now that we're testing GettingStarted tests with an actual registration, Jenkins needs to pass in the password so the CAPTCHA can be bypassed. The support for doing this (given the password) was recently merged into GettingStarted: https://git.wikimedia.org/blob/mediawiki%2Fextensions%2FGettingStarted.git/554a2e12d4855c00f2e6d7145f3d528bc9563db0/tests%2Fbrowser%2Ffeatures%2Fsupport%2Fpages%2Fregistration_page.rb .
Until this is done, the tests will fail.