Fix CORS issue using Mongo Shell from new origin (#1422)

* Fix CORS issue using Mongo Shell from new origin

* Add unit tests for getMongoShellOrigin and getMongoShellUrl

* Fix lint errors

src/Explorer/Tabs/MongoShellTab/getMongoShellOrigin.test.ts

@@ -0,0 +1,73 @@
+import { extractFeatures } from "Platform/Hosted/extractFeatures";
+import { configContext } from "../../../ConfigContext";
+import { updateUserContext } from "../../../UserContext";
+import { getMongoShellOrigin } from "./getMongoShellOrigin";
+
+describe("getMongoShellOrigin", () => {
+  (window as { origin: string }).origin = "window_origin";
+
+  beforeEach(() => {
+    updateUserContext({
+      features: extractFeatures(
+        new URLSearchParams({
+          "feature.enableLegacyMongoShellV1": "false",
+          "feature.enableLegacyMongoShellV2": "false",
+          "feature.enableLegacyMongoShellV1Dist": "false",
+          "feature.enableLegacyMongoShellV2Dist": "false",
+        })
+      ),
+    });
+  });
+
+  it("should return BACKEND_ENDPOINT by default", () => {
+    expect(getMongoShellOrigin()).toBe(configContext.BACKEND_ENDPOINT);
+  });
+
+  it("should return /mongoshell/index.html when enableLegacyMongoShellV1", () => {
+    updateUserContext({
+      features: extractFeatures(
+        new URLSearchParams({
+          "feature.enableLegacyMongoShellV1": "true",
+        })
+      ),
+    });
+
+    expect(getMongoShellOrigin()).toBe(window.origin);
+  });
+
+  it("should return /mongoshell/index.html when enableLegacyMongoShellV2===true", () => {
+    updateUserContext({
+      features: extractFeatures(
+        new URLSearchParams({
+          "feature.enableLegacyMongoShellV2": "true",
+        })
+      ),
+    });
+
+    expect(getMongoShellOrigin()).toBe(window.origin);
+  });
+
+  it("should return /mongoshell/index.html when enableLegacyMongoShellV1Dist===true", () => {
+    updateUserContext({
+      features: extractFeatures(
+        new URLSearchParams({
+          "feature.enableLegacyMongoShellV1Dist": "true",
+        })
+      ),
+    });
+
+    expect(getMongoShellOrigin()).toBe(window.origin);
+  });
+
+  it("should return /mongoshell/index.html when enableLegacyMongoShellV2Dist===true", () => {
+    updateUserContext({
+      features: extractFeatures(
+        new URLSearchParams({
+          "feature.enableLegacyMongoShellV2Dist": "true",
+        })
+      ),
+    });
+
+    expect(getMongoShellOrigin()).toBe(window.origin);
+  });
+});