Update MS-700-lab_M01_ak.md

[ITBlandMCT]

Need to add "At the ‘Stay signed in to all your apps’ window, select No, sign in to this app only." when Alex signs (So that Lynne can sign in using the web in the next task.

Module: 01

Lab: 01

Exercise 3

Task 2

Step 3

Changes proposed in this pull request:

• add "At the ‘Stay signed in to all your apps’ window, select No, sign in to this app only." when Alex signs in so that Lynne can also sign in using the web in the next task.