Fix useIsAuthenticated hook briefly returning false even though the user is authenticated

[hatched-kade]

Addresses #6918

The current useIsAuthenticated has an unnecessary useEffect, which causes it to briefly return false in some cases even when an account is present. See https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state and https://react.dev/learn/you-might-not-need-an-effect#caching-expensive-calculations

This PR switches to use the useMemo recommendation

I added a unit test that passes now, but fails with the old implementation:

 FAIL  test/hooks/useIsAuthenticated.spec.tsx
  ● withMsal tests › useAuthenticated always returns true if user has an account

    expect(jest.fn()).toHaveBeenCalledTimes(expected)

    Expected number of calls: 0
    Received number of calls: 1

      78 |         expect(await screen.findByText("Has accounts")).toBeInTheDocument();
      79 |         expect(await screen.findByText("Is authed")).toBeInTheDocument();
    > 80 |         expect(invalidAuthStateCallback).toHaveBeenCalledTimes(0);
         |                                          ^
      81 |     });
      82 | });
      83 |

      at Object.<anonymous> (test/hooks/useIsAuthenticated.spec.tsx:80:42)

I also had to tweak some act / await / async code in other tests, presumably because now it takes fewer renders for the hook to start returning the correct value. Without the tweaks a couple tests were failing, and others printed warning about updating state outside of an act(...).

[hatched-kade]

@microsoft-github-policy-service agree company="Giant Eagle"

[tnorling]

Thanks for the PR! I imagine there's other places we can make similar changes.

[jo-arroyo]

Looks great, small nit

[aleks-sch]

thanks @hatched-kade!

@tnorling @jo-arroyo could we (you) do a release of msal-react please?

we are also impacted by #6918 and would rather not install from dev branch. thanks