Update Measurement info on the fly

Summary: The Features of a PlanarFigure (e.g. length of a line) are already updated while a control point is moved, but the text in the Measurement plugin is not. With the new event, this info is updated live during movement of the point.

Test Plan: Load any picture, create any measurement, see how the info text in the Measurement plugin is updated while moving a point during creation or afterwards

Reviewers: O1 MITK Reviewer Group I, kislinsk

Reviewed By: O1 MITK Reviewer Group I, kislinsk

Maniphest Tasks: T27263

Differential Revision: https://phabricator.mitk.org/D579