XFA - Avoid an error when an exdata is a string (bug 1723114)

src/core/xfa/template.js

@@ -5905,6 +5905,9 @@ class Value extends XFAObject {
 
   [$text]() {
     if (this.exData) {
+      if (typeof this.exData[$content] === "string") {
+        return this.exData[$content].trim();
+      }
       return this.exData[$content][$text]().trim();
     }
     for (const name of Object.getOwnPropertyNames(this)) {

test/pdfs/xfa_bug1722038.pdf.link

@@ -0,0 +1 @@
+https://bugzilla.mozilla.org/attachment.cgi?id=9232853

test/test_manifest.json

@@ -952,6 +952,14 @@
        "enableXfa": true,
        "type": "eq"
     },
+    {  "id": "xfa_bug1722038",
+       "file": "pdfs/xfa_bug1722038.pdf",
+       "md5": "95170baaade2ab6e1d0372f35db01747",
+       "link": true,
+       "rounds": 1,
+       "enableXfa": true,
+       "type": "eq"
+    },
     {  "id": "xfa_bug1720888",
        "file": "pdfs/xfa_bug1720888.pdf",
        "md5": "3a9486b851b7d069c3cb31b0be2bc2ff",