PHP 7.2 error when using the integrated theme settings in Content Templates

Symptoms

When using one of the integrated themes that provide their options to Content Templates, Views will produce an error if running under PHP 7.2.

Workaround

This issue will be solved in the next version of Views. In the meantime, this patch can be used by unzipping it and uploading the file it contains, replacing the one with the same name, located in /vendor/toolset/toolset-theme-settings/compatibility-modules/controllers/.