Change in location of chest_skin_frame in some legacy DH-generated iCub models after focal upgrade

[traversaro]

After https://github.com/robotology/icub-model-generator/pull/134, the icub-models were regenerated in https://github.com/robotology/icub-models/commit/472db4555ea72832db571b49197849e1fc6192f1 . For simmechanics all the changes seems just that floating point numbers are printed with higher precision, but for some dh-generated models the location of the chest_skin_frame changed significantly, from:

        <origin xyz="0.00231 0.1933 -1.18362e-17" rpy="-1.8747e-33 5.77686e-66 6.16298e-33" />

to

        <origin xyz="-0.0055 -0.032 3.36778e-19" rpy="1.5708 -1.22465e-16 -3.14159" />

while this model are seldom used, it may be important to understand what happened.

[traversaro]

At a first check, the chest_skin_frame is computed in https://github.com/robotology/idyntree/blob/c8bf721b771fa4b1e7c3a940632e121060719a19/src/legacy/icub-kdl/src/idyn2kdl_icub.cpp#L492 by computing the transform between the chest frame in the URDF, and the transform in which the point of the skin are expressed, that is specified by the iCubTorso iKin chain. The rationale for this is provided in https://github.com/robotology/icub-main/issues/124 . From that, I would guess that the something changed in iCubTorso transform from ICUB 1.13 to 1.17, but the only related change do not seem to change anything:

• https://github.com/robotology/icub-main/pull/629

However, it is possible that also something else in all the other dependencies that changed is affecting this.