Apply busy indicator duration change of D22646 to the QQC2 style
Summary:
Match the duration (2 seconds) that was set in D22630.
This style is mainly used by Plasma Mobile, therefore requesting team review from that project as well.
Reviewers: VDG, Plasma:_mobile, ngraham
Reviewed By: VDG, ngraham
Subscribers: ngraham, kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D22720