SuperSize: Fix requiresAuthentication() when query string is not escaped

E.g. chromium-binary-size-trybot-results%2Fandroid-binary-size
 vs: chromium-binary-size-trybot-results/android-binary-size

Bug: 1131568
Change-Id: I8801d04748d0d21bb4bdf2a63a56f78445a23160
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503634
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Mohamed Heikal <mheikal@chromium.org>
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821453}

tools/binary_size/libsupersize/static/auth.js

@@ -39,8 +39,9 @@ function setSigninStatus() {
 
 function requiresAuthentication() {
   // Assume everything requires auth except public trybot and one-offs.
-  const isPublicTrybot = window.location.search.indexOf(
-      'chromium-binary-size-trybot-results%2Fandroid-binary-size') != -1;
-  const isOneOff = window.location.search.indexOf('%2Foneoffs%2F') != -1;
+  const queryString = decodeURIComponent(location.search);
+  const isPublicTrybot = queryString.indexOf(
+      'chromium-binary-size-trybot-results/android-binary-size') != -1;
+  const isOneOff = queryString.indexOf('/oneoffs/') != -1;
   return !isPublicTrybot && !isOneOff;
 }