Always allow chrome://terminal since it is used for crosh

The TerminalSystemApp feature flag will still control
whether the new terminal app is shown, but we will always
allow chrome://terminal to serve content since it is now
used for crosh.

Bug: 1022250
Change-Id: I5feae6e4d6cfe5bf7fd830d27f55a343d390fb6a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1924330
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#716927}

chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc

@@ -556,11 +556,8 @@ WebUIFactoryFunction GetWebUIFactoryFunction(WebUI* web_ui,
     return &NewWebUI<chromeos::smb_dialog::SmbShareDialogUI>;
   if (url.host_piece() == chrome::kChromeUISysInternalsHost)
     return &NewWebUI<SysInternalsUI>;
-  if (url.host_piece() == chrome::kChromeUITerminalHost) {
-    if (!base::FeatureList::IsEnabled(features::kTerminalSystemApp))
-      return nullptr;
+  if (url.host_piece() == chrome::kChromeUITerminalHost)
     return &NewWebUI<TerminalUI>;
-  }
   if (url.host_piece() == chrome::kChromeUIAssistantOptInHost)
     return &NewWebUI<chromeos::AssistantOptInUI>;
   if (url.host_piece() == chrome::kChromeUICameraHost &&