(core) Making makeT helper use the unprefixed key as a fallback

Summary:
By default the fallback contains the prefix, which doesn't
work well with a key based translations. Now makeT helper will fallback
to the passed key (without a prefix).

Test Plan: Added new client test

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: paulfitz

Differential Revision: https://phab.getgrist.com/D3758

test/client/lib/localization.ts

@@ -127,4 +127,9 @@ describe('localization', function() {
     const scoped = makeT('Parent', instance);
     assert.equal(scoped('Not.Valid:Characters'), 'Works');
   });
+
+  it('makeT helper fallbacks to an argument', function() {
+    const scoped = makeT('Parent', instance);
+    assert.equal(scoped("I'm not there"), "I'm not there");
+  });
 });