Update azure-ad-join-technician-flow.md

[matthewjlevy]

Corrected number of next step (this is step 8 and so next step is step 9: User flow)

[prmerger-automator]

@matthewjlevy : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[learn-build-service-prod]

Learn Build status updates of commit d07daac:

✅ Validation status: passed

File	Status	Preview URL	Details
autopilot/tutorial/pre-provisioning/azure-ad-join-technician-flow.md	✅Succeeded

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[frankroj]

Thanks for catching this typo @matthewjlevy. It should go live later today.

[frankroj]

#sign-off