feat(client): ts-migrate /client/src/analytics (#42457)

* migrate to ts

* fix empty function for linting

* add function return type

Co-authored-by: Parth Parth <thecodingaviator@users.noreply.github.com>

client/src/analytics/__mocks__/index.js

@@ -1,5 +0,0 @@
-const analytics = {
-  event: () => {}
-};
-
-export default analytics;

client/src/analytics/__mocks__/index.tsx

@@ -0,0 +1,7 @@
+const analytics = {
+  event: function (): void {
+    // comment necessary for linting.
+  }
+};
+
+export default analytics;