Revert "Hide Enpass until it's supported in muon"

This reverts commit 29a8223.

According to issue brave#7778, particularly the comment by @mcg, support for
Enpass is already working. So the option can be re-enabled.

Fixes brave#7778, brave#5097, brave#6984.

js/about/preferences.js

@@ -622,7 +622,7 @@ class SecurityTab extends ImmutableComponent {
             <option data-l10n-id='dashlane' value={passwordManagers.DASHLANE} />
             <option data-l10n-id='lastPass' value={passwordManagers.LAST_PASS} />
             <option data-l10n-id='bitwarden' value={passwordManagers.BITWARDEN} />
-            { /* <option data-l10n-id='enpass' value={passwordManagers.ENPASS} /> */ }
+            <option data-l10n-id='enpass' value={passwordManagers.ENPASS} />
             <option data-l10n-id='doNotManageMyPasswords' value={passwordManagers.UNMANAGED} />
           </SettingDropdown>
         </SettingItem>