fix WidgetColor import Issue #3776

[shroffk]

fixes #3776
maintains backward compatibility as described in the comments

Checklist

• Testing:

  • The feature has automated tests
  • Tests were run
  • If not, explain how you tested your changes

• Documentation:

  • The feature is documented

[kasemir]

Not sure I want to update every script on our control system.
Maybe add the old WidgetColor back in:

package org.csstudio.display.builder.model.properties

// Class in original package that wraps the new one to satisfy
// existing scripts
public class WidgetColor extends org.phoebus.ui.color.WidgetColor
{

}

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud