browser(firefox): disable the extension blocklist (#1909)

This saves a few hundred milliseconds.

Author: JoelEinbinder

browser_patches/firefox/BUILD_NUMBER

@@ -1 +1 @@
-1084
+1085

browser_patches/firefox/preferences/playwright.cfg

@@ -249,5 +249,8 @@ lockPref("toolkit.crashreporter.enabled", false);
 pref("toolkit.telemetry.enabled", false);
 pref("toolkit.telemetry.server", "");
 
+// Disable downloading the list of blocked extensions.
+pref("extensions.blocklist.enabled", false);
+
 // Disable crash reporter.
 Components.classes["@mozilla.org/toolkit/crash-reporter;1"].getService(Components.interfaces.nsICrashReporter).submitReports = false;