Add areErrorsEqual equality tester

- This was done to make sure `toHaveBeenCalledWith` will fail if we pass in the wrong Error constructor. For example the assertion will now fail if we pass in an `Error` instead of a `TypeError`.

Author: aryaemami59

packages/toolkit/vitest.setup.ts

@@ -5,6 +5,22 @@ vi.stubGlobal('fetch', nodeFetch)
 vi.stubGlobal('Request', Request)
 vi.stubGlobal('Headers', Headers)
 
+/**
+ * Compares two values to determine if they are instances of {@linkcode Error}
+ * and have the same `name` and `message` properties.
+ *
+ * @param a - The first value to compare.
+ * @param b - The second value to compare.
+ * @returns `true` if both values are instances of {@linkcode Error} and have the same `name` and `message`.
+ */
+const areErrorsEqual = (a: unknown, b: unknown) => {
+  if (a instanceof Error && b instanceof Error) {
+    return a.name === b.name && a.message === b.message
+  }
+}
+
+expect.addEqualityTesters([areErrorsEqual])
+
 beforeAll(() => {
   server.listen({ onUnhandledRequest: 'error' })
 })