Fix helpers not working in e2e tests

It errors that jest is not defined so put it behind a function instead
of immediately creating the mock (this is probably a better pattern
anyway).

The constant tests had to be reworked a little. Since the logger mock is
hoisted it runs before createLoggerMock is imported. I moved it into a
beforeAll which means the require call also needed to be moved
there (since we need to mock the logger before requiring the constants
or it'll pull the non-mocked logger).

This means getPackageJson needs to be a let and assigned afterward. To
avoid having to define a type for getPackageJson I just added a let var
set to the type of the imported constants file and modified the other
areas to use the same paradigm.

I also replaced some hardcoded strings with the mocked package.json
object.

test/unit/util.test.ts

@@ -11,7 +11,7 @@ import {
   trimSlashes,
   normalize,
 } from "../../src/common/util"
-import { loggerModule } from "../utils/helpers"
+import { createLoggerMock } from "../utils/helpers"
 
 const dom = new JSDOM()
 global.document = dom.window.document
@@ -229,6 +229,8 @@ describe("util", () => {
       jest.restoreAllMocks()
     })
 
+    const loggerModule = createLoggerMock()
+
     it("should log an error with the message and stack trace", () => {
       const message = "You don't have access to that folder."
       const error = new Error(message)