Remove enroll animation from touch sensor page

During the setup flow, the enrolling animation will be shown in the
touch sensor page. This was caused by using the old layout during the
setup flow. Removing the overrided method getContentView to fix this
issue.

Fixes: 179447737
Test: visual verified
1) adb shell am start -n
com.google.android.setupwizard/.SetupWizardTestActivity
2) Follow the setup flow and check if the touch sensor page has an
animation

Change-Id: I249535d6c0e8a5f12d86aeeac5308489e469bf71