fixup! MB 38: Mullvad Browser configuration

TB 43653: Remove the unused spoofOsInUserAgentHeader pref.

browser/app/profile/000-mullvad-browser.js

@@ -24,8 +24,5 @@ pref("browser.shell.checkDefaultBrowser", false);
 // mullvad-browser#228: default to spoof en-US and skip showing the dialog
 pref("privacy.spoof_english", 2);
 
-// mullvad-browser#234: Do not spoof the OS in the User-Agent header
-pref("privacy.resistFingerprinting.spoofOsInUserAgentHeader", false);
-
 // mullvad-browser#222: Hide "List all tabs" when the tabs don't overflow
 pref("browser.tabs.tabmanager.enabled", false);