PageBuilder UI elements are coming back as resx name instead of value.

[epperson]

Brief bug description

UI elements displayed in the PageBuilder interface in a Kentico 12.0.30 project display resx name instead of value.

Repro steps

Add NuGet package to project running Kentico 12.0.30 with at least one page utilizing PageBuilder widgets.

Expected behavior

Values from CMS.resx would be displayed instead of the names.

Test environment

• Platform/OS: Windows 10
• Browser Chrome
• Version 76.0.3809.100

Additional context

N/A

Screenshots

[yuriys-kentico]

This appears similar to when the RESX files aren't copied to the build output, which was fixed in 12.0.13. Do the RESX files exist in the MVC application's filesystem?