Replace deprecated SimilarityTransform.estimate() with SimilarityTransform.from_estimate()

[tommycarstensen]

scikit-image 0.26 deprecated SimilarityTransform.estimate() in favor of the SimilarityTransform.from_estimate() class constructor (scikit-image#7771). It will be removed in scikit-image 2.2.

This produces a FutureWarning on every face alignment call:

insightface/utils/face_align.py:23: FutureWarning: `estimate` is deprecated since version 0.26
and will be removed in version 2.2. Please use `SimilarityTransform.from_estimate` class
constructor instead.

The fix is a one-liner in insightface/utils/face_align.py:

# Before
tform = SimilarityTransform()
tform.estimate(dst, src)

# After
tform = SimilarityTransform.from_estimate(dst, src)

Environment: insightface 0.7.3, scikit-image 0.26.0, Python 3.13