fix(headPoseEstimation): Rename attribute name according to changes in mediapipe library.

[xmajzel]

Mediapipe library has renamed attribute name, causing following error:

AttributeError: module 'mediapipe.python.solutions.face_mesh' has no attribute 'FACE_CONNECTIONS'

Resources:

• https://github.com/google/mediapipe/blob/master/mediapipe/python/solutions/holistic.py
• AttributeError: module 'mediapipe.python.solutions.face_mesh' has no attribute 'FACE_CONNECTIONS' google-ai-edge/mediapipe#2448

[xmajzel]

Alternatively FACEMESH_CONTOURS attribute can be used, see attached photos for differences bellow.

FACEMESH_CONTOURS:

FACEMESH_TESSELATION:

[xmajzel]

@niconielsen32