[FIX] Only escape HTML from details in toast error messages (#11459)

* Only escape HTML from details in toast error messages

* Refactor reducer

client/lib/handleError.js

@@ -12,7 +12,12 @@ this.handleError = function(error, useToastr = true) {
 	}
 
 	if (useToastr) {
-		return toastr.error(s.escapeHTML(TAPi18n.__(error.error, error.details)), error.details && error.details.errorTitle ? s.escapeHTML(TAPi18n.__(error.details.errorTitle)) : null);
+		const details = Object.entries(error.details || {})
+			.reduce((obj, [ key, value ]) => ({ ...obj, [key] : s.escapeHTML(value) }), {});
+		const message = TAPi18n.__(error.error, details);
+		const title = details.errorTitle && TAPi18n.__(details.errorTitle);
+
+		return toastr.error(message, title);
 	}
 
 	return s.escapeHTML(TAPi18n.__(error.error, error.details));