Get the first codepoint instead of the first char when using the toUnicode map

It fixes #19182.

src/core/to_unicode_map.js

@@ -28,7 +28,7 @@ class ToUnicodeMap {
 
   forEach(callback) {
     for (const charCode in this._map) {
-      callback(charCode, this._map[charCode].charCodeAt(0));
+      callback(charCode, this._map[charCode].codePointAt(0));
     }
   }
 

test/pdfs/.gitignore

@@ -687,3 +687,4 @@
 !rotated_ink.pdf
 !inks.pdf
 !inks_basic.pdf
+!issue19182.pdf

test/test_manifest.json

@@ -11201,5 +11201,12 @@
         "id": "20R"
       }
     }
+  },
+  {
+    "id": "issue19182",
+    "file": "pdfs/issue19182.pdf",
+    "md5": "497370ab55cbb9c60bb0ea4b5d9e4d08",
+    "rounds": 1,
+    "type": "eq"
   }
 ]