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