refactor: update imports to use ES module syntax and improve test structure (#1350)

- Changed import statements across multiple files to use the .js extension for ES module compatibility.
- Refactored test files to utilize jest's unstable_mockModule for mocking core actions.
- Removed unnecessary spy instances in tests, replacing them with direct mocked function calls.
- Updated TypeScript configuration to target ES2022 and use NodeNext module resolution.
- Removed the tsconfig.spec.json file and adjusted the main tsconfig.json to exclude test files.

tsconfig.app.json

@@ -1,5 +1,5 @@
 {
   "extends": "./tsconfig.json",
-  "exclude": ["node_modules", "**/*.spec.ts"],
+  "exclude": ["**/*.spec.ts"],
   "include": ["src"]
 }