Automated response: Changing any public config options should trigger template cache flush

Because public config values are stored in JavaScript configOptionsJson variable through a Tempcode symbol, changing any public configuration options should trigger an automatic template cache flush so this value is updated and is not stale.

This hotfix makes setting any public config option flush specifically the _cms and global template caches (rather than doing a full template cache flush, which is not necessary). These are responsible for holding public config values for JavaScript.