Refactor browser dropdown links and components (#5562)

* refactor browser links and about modal

Moved about modal to separate component and added unit tests.

* refactor change password modal component

* added unit tests for ChangePasswordModal

* fix logout function in browser dropdown

* remove older unused BrowserDropdown component

* remove unused variables from BrowserDropdown component

* show BrowserDropdown and StorageInfo only for LoggedIn users

Non-loggedIn users will see a 'Login' button

browser/app/js/browser/__tests__/Header.test.js

@@ -18,8 +18,25 @@ import React from "react"
 import { shallow } from "enzyme"
 import Header from "../Header"
 
+jest.mock("../../web", () => ({
+  LoggedIn: jest
+    .fn(() => true)
+    .mockReturnValueOnce(true)
+    .mockReturnValueOnce(false)
+}))
 describe("Header", () => {
   it("should render without crashing", () => {
     shallow(<Header />)
   })
+
+  it("should render Login button when the user has not LoggedIn", () => {
+    const wrapper = shallow(<Header />)
+    expect(wrapper.find("a").text()).toBe("Login")
+  })
+
+  it("should render StorageInfo and BrowserDropdown when the user has LoggedIn", () => {
+    const wrapper = shallow(<Header />)
+    expect(wrapper.find("Connect(BrowserDropdown)").length).toBe(1)
+    expect(wrapper.find("Connect(StorageInfo)").length).toBe(1)
+  })
 })