[SDXL-Turbo] Add SDXL-Turbo scheduler to from_single_file

[tolgacangoz]

What does this PR do?

Fixes #6112.
Previously from_single_file chose EulerDiscreteScheduler as a scheduler for SDXL and SDXL-Refiner; but now, SDXL-Turbo needs EulerAncestralDiscreteScheduler with proper parameters.

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