QDS-14556 Extend tests

This MR brings the following changes;

• fix: design studio manager does not fire disconnected signal
• add: a new function to reset the settings
• tests: new tests for design studio integration, settings, and project management
• tests: test app now has the same app-icon with the Qt UI Viewer
• doc: update README to fix the xunit-viewer usage example
• cicd: build single multi-arch aab that contains all available platforms (QDS-14698)