Modified blob creation in mesh quality optimizer to take "onlyValidity" parameter into account

git-svn-id: https://geuz.org/svn/gmsh/trunk@19845 59c8cabf-10d6-4a28-b43f-3936b85956c4
git-svn-id: https://geuz.org/svn/gmsh/trunk@19846 59c8cabf-10d6-4a28-b43f-3936b85956c4