Ensure that readonly TextWidget-annotations are rendered when forms are disabled (issue 17064)

To reduced the risk of regressing something else, given that the issue only applies to a (for the default viewer) non-default configuration, this patch is purposely limited to only TextWidget-annotations in the display layer.

test/pdfs/.gitignore

@@ -119,6 +119,7 @@
 !issue7891_bc0.pdf
 !issue11242_reduced.pdf
 !issue16176.pdf
+!issue17064_readonly.pdf
 !issue11279.pdf
 !issue11362.pdf
 !issue13325_reduced.pdf

test/test_manifest.json

@@ -3143,6 +3143,13 @@
       "link": true,
       "type": "eq"
     },
+    {  "id": "issue17064_readonly",
+       "file": "pdfs/issue17064_readonly.pdf",
+       "md5": "cb84f8e8301e935a3b9ea8ef320f45bf",
+       "rounds": 1,
+       "type": "eq",
+       "annotations": true
+    },
     {  "id": "issue12714",
        "file": "pdfs/issue12714.pdf",
        "md5": "f9ee31c74f9e342e95122b0b3bc84fa0",