Revert "Update first ACE tutorial to SPFx 1.18"

[VesaJuvonen]

Reverts #9022

[learn-build-service-prod]

Learn Build status updates of commit 5850f2c:

❌ Validation status: errors

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File	Status	Preview URL	Details
	❌Error		Details

• [Error: GitBranchDeletedOrForcePushed]

Cannot sync git repo to specified commit because ref +refs/pull/9045/merge has been deleted or has been force pushed.
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