terminal: remove prefs terminal-emulator and the dropdown in settings

We don't want to show the dropdown for the public launch. This CL also
switch tests in terminal_tests.js to use xterm.js.

Bug: b/236205389
Change-Id: Ie81b6e3b8482581f885ed5c6ad76c2d607c6a733
Reviewed-on: https://chromium-review.googlesource.com/c/apps/libapps/+/4022727
Reviewed-by: Joel Hockey <joelhockey@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/terminal/js/terminal_emulator.js b/terminal/js/terminal_emulator.js
index 85f66de..190961b 100644
--- a/terminal/js/terminal_emulator.js
+++ b/terminal/js/terminal_emulator.js
@@ -1326,8 +1326,7 @@
     // TODO: remove the url param logic. This is temporary to make manual
     // testing a bit easier, which is also why this is not in
     // './js/terminal_info.js'.
-    const emulator = ORIGINAL_URL.searchParams.get('emulator') ||
-        await storage.getItem(`/hterm/profiles/${profileId}/terminal-emulator`);
+    const emulator = ORIGINAL_URL.searchParams.get('emulator');
     // Use the default (i.e. first) one if the pref is not set or invalid.
     config = TERMINAL_EMULATORS.get(emulator) ||
         TERMINAL_EMULATORS.values().next().value;