[osg] Disable conditional plugins.

[BillyONeal]

Resolves nightly CI failure:

       "D:\buildtrees\osg\x86-windows-dbg\install.vcxproj" (default target) (1) ->
       "D:\buildtrees\osg\x86-windows-dbg\ALL_BUILD.vcxproj" (default target) (3) ->
       "D:\buildtrees\osg\x86-windows-dbg\src\osgPlugins\OpenCASCADE\osgdb_opencascade.vcxproj" (default target) (54) ->
       (ClCompile target) ->
         D:\buildtrees\osg\src\raph-3.6.5-0028e69d98.clean\src\osgPlugins\OpenCASCADE\ReaderWriterOpenCASCADE.cpp(214,49): error C2039: 'Nodes': is not a member of 'Poly_Triangulation' [D:\buildtrees\osg\x86-windows-dbg\src\osgPlugins\OpenCASCADE\osgdb_opencascade.vcxproj]

Opencascade disabled because it's broken.

All others disabled because they were behind some kind of if (XXX_found) in src\osgPlugins\CMakeLists.tx, except, Quicktime left alone because that's part of MacOS?

[github-actions]

You have modified or added at least one portfile where deprecated functions are used.

Details

If you feel able to do so, please consider migrating them to the new functions:
vcpkg_install_cmake -> vcpkg_cmake_install (from port vcpkg-cmake)
vcpkg_build_cmake -> vcpkg_cmake_build (from port vcpkg-cmake)
vcpkg_configure_cmake -> vcpkg_cmake_configure (Please remove the option PREFER_NINJA) (from port vcpkg-cmake)
vcpkg_fixup_cmake_targets -> vcpkg_cmake_config_fixup (from port vcpkg-cmake-config)

In the ports that use the new function, you have to add the corresponding dependencies:

{
  "name": "vcpkg-cmake",
  "host": true
},
{
  "name": "vcpkg-cmake-config",
  "host": true
}

The following files are affected:

• ports/osg/portfile.cmake

[BillyONeal]

BTW the trigger for the CI failure was having opencascade installed first.