[api-minor] Don't add in the text content the chars which are out-of-page (bug 1755201)

- it aims to fix https://bugzilla.mozilla.org/show_bug.cgi?id=1755201;
- if the glyph position is not within the view then skip it.

src/core/document.js

@@ -471,6 +471,7 @@ class Page {
         includeMarkedContent,
         combineTextItems,
         sink,
+        viewBox: this.view,
       });
     });
   }