Bug 1919071 - Remove the unused pdfjs.enableFloatingToolbar preference. r=pdfjs-reviewers,calixte

This preference was removed upstream in https://github.com/mozilla/pdf.js/pull/16605, which was uplifted in https://bugzilla.mozilla.org/show_bug.cgi?id=1840990, hence the override should also be removed now.

Differential Revision: https://phabricator.services.mozilla.com/D222306

toolkit/components/pdfjs/PdfJsOverridePrefs.js

@@ -18,9 +18,6 @@
   // Editing PDFs is not supported on mobile
   pref("pdfjs.annotationEditorMode", -1);
 
-  // Enable the floating PDF.js toolbar on GeckoView (bug 1829366)
-  pref("pdfjs.enableFloatingToolbar", true);
-
 #else
 
   #if defined(EARLY_BETA_OR_EARLIER)

toolkit/components/pdfjs/test/test_pdf_file_in_iframe.html

@@ -16,10 +16,7 @@
 
           async function test() {
             await SpecialPowers.pushPrefEnv({
-              "set": [
-                ["pdfjs.disabled", false],
-                ["pdfjs.enableFloatingToolbar", false],
-              ],
+              "set": [["pdfjs.disabled", false]],
             });
 
             const iframe = document.createElement("iframe");