VS: Adapt project parsers to support "ProjectGUID" without curly brackets

This is needed to correctly parse Windows Installer "wiproj" projects,
that by default contain "ProjectGUID" tags with GUID values without
surrounding curly brackets.  Otherwise CMake truncates the first & last
character from the GUID value for these projects.
21 jobs for ProjectGUID-brackets
Status Job ID Name Coverage
  External
passed ghostflow-branch-check-master

passed ghostflow-commit-check

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager