test: Move cli e2e test to typegate/tests/e2e (#492)

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### Describe your change

Move CLI e2e tests to typegate/tests/e2e

### Motivation and context

[MET-208](https://metatype.atlassian.net/browse/MET-208)


### Checklist

- [x] The change come with new or modified tests
- [x] Hard-to-understand functions have explanatory comments
- [x] End-user documentation is updated to reflect the change

---------

Co-authored-by: Yohe-Am <56622350+Yohe-Am@users.noreply.github.com>

typegate/tests/e2e/typegraph/validator_test.ts

@@ -0,0 +1,22 @@
+// Copyright Metatype OÜ, licensed under the Elastic License 2.0.
+// SPDX-License-Identifier: Elastic-2.0
+
+import { TestModule } from "test-utils/test_module.ts";
+import { Meta } from "test-utils/mod.ts";
+import { assert } from "std/assert/mod.ts";
+
+const m = new TestModule(import.meta);
+
+Meta.test("typegraph validation", async (t) => {
+  await t.should(
+    "fail to serialize typegraph with invalid injection",
+    async () => {
+      try {
+        await m.cli({}, "serialize", "-f", "typegraphs/python/validator.py");
+        assert(false, "should have thrown");
+      } catch (e) {
+        await t.assertSnapshot(e.message);
+      }
+    },
+  );
+});