Revert "Disable DeviceDiagnosticsPreferenceController."

This reverts commit 2c0c79d05d60fd08305171bf92f8abc4caf2d0ec.

Reason for revert: build break
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8183830db2eafed0a996091afe49ea39ae15e1c6)
Merged-In: I82c1a11c85f29c63ee4f0b6827df8b384cec1a09
Change-Id: I82c1a11c85f29c63ee4f0b6827df8b384cec1a09
1 file changed