Make ProgressInidcatorConnector use VProgressIndicator (#11925)

When ProgressBar was split out from ProgressIndicator,
ProgressIndicatorConnector was accidentally left inheriting the
VProgressBar widget from ProgressBarConnector instead of using its own
VProgressIndicator.

Change-Id: Ie7c5d3b68af871d5eb2a86f3d720af3b23048793