fix: CozyClient can be used in a node env

[Ldoppea]

Previous fix tried to handle undefined window in node env

But in a node env window is not undefined as it is not even an
existing variable

So instead of checking its value, a better way is to check its type as
typeof will return 'undefined' when called with a variable that
does not exist

Related commit: 509a0ca

Warning
This fix cannot be unit tested until #1179 - Current tests are not covering Node environment is resolved

Following test is success with the new fix if run from a node env

    it('should not secure the URL if window is not existing (node env)', () => {
      const client = new CozyClient({
        uri: 'http://cozy.tools',
        schema: '',
        token: 'SOME_TOKEN'
      })

      expect(client.options.uri).toBe('http://cozy.tools')
    })

Following test is success with the new fix if run from a jsdom env

    it('should not secure the URL if window is undefined (node env)', () => {
      let windowSpy = jest.spyOn(window, 'window', 'get')
      windowSpy.mockImplementation(() => undefined)
      const client = new CozyClient({
        uri: 'http://cozy.tools',
        schema: '',
        token: 'SOME_TOKEN'
      })

      expect(client.options.uri).toBe('http://cozy.tools')
      windowSpy.mockRestore()
    })

[paultranvan]

Thanks 🎉