Regression in estimation of redundant external forces since August 2022

[traversaro]

In https://github.com/robotology/idyntree/pull/1017 there was a regression when the forces are redundant.

By the way, I suspect the reason of the sharp changes in the estimated FT may be https://github.com/robotology/idyntree/pull/1017 , even if also colPivHouseholderQr should return the least square solution. However, https://github.com/robotology/idyntree/pull/1017 changed a truncated pseudo-inverse for a non-truncated one, something that I missed while reviewing https://github.com/robotology/idyntree/pull/1017 .

colPivHouseholderQr should return the least square solution

Probably it returns the least-square solution in the case of equation then unknown, not more unknown that equations (that is the case now).