Show usage hint when drawing planar figures
Summary:
In addition, in case of continuous planar figures make clear that a double click is necessary to end interaction.
Fixes T30416.
Test Plan: Draw planar figures with the Measurement view and check if the usage hint(s) are shown and hidden accordingly.
Reviewers: O1 MITK Reviewer Group I!
Maniphest Tasks: T30416
Differential Revision: https://phabricator.mitk.org/D944