Blank string is valid for cmi.core.exit/cmi.exit

src/cmi/scorm12_cmi.js

@@ -462,7 +462,7 @@ class CMICore extends BaseCMI {
    * @param {string} exit
    */
   set exit(exit) {
-    if (check12ValidFormat(exit, regex.CMIExit)) {
+    if (check12ValidFormat(exit, regex.CMIExit, true)) {
       this.#exit = exit;
     }
   }

src/cmi/scorm2004_cmi.js

@@ -235,7 +235,7 @@ export class CMI extends BaseCMI {
    * @param {string} exit
    */
   set exit(exit) {
-    if (check2004ValidFormat(exit, regex.CMIExit)) {
+    if (check2004ValidFormat(exit, regex.CMIExit, true)) {
       this.#exit = exit;
     }
   }

src/constants/field_values.js

@@ -89,6 +89,7 @@ export const scorm12_values = {
       'time-out',
       'suspend',
       'logout',
+      '',
     ],
     invalidExit: [
       'close',
@@ -229,6 +230,7 @@ export const scorm2004_values = {
       'suspend',
       'logout',
       'normal',
+      '',
     ],
     invalidExit: [
       'close',