Make settings tests more reliable (fixing widget naming).

Fixed how widgets are named in pqSettingsDialog to make test playback
more reliable. When plugins that added new settings were loaded, we were
ending up with failed tests since the names of the widgets in
pqSettingsDialog could potentially change. Fixed that.

Change-Id: I74f401f6b689cab39c7b2b69d6f18bf0120ae0bd
Merge topic 'lookup_table_cleanup' into next

eb1a26ee Make settings tests more reliable (fixing widget naming).