App: Remove build dependency to Coin3D

Fixes https://github.com/FreeCAD/FreeCAD/issues/20897

src/App/Application.cpp

@@ -67,7 +67,6 @@
 #include <QRegularExpression>
 #include <QSettings>
 #include <QStandardPaths>
-#include <Inventor/C/basic.h>
 #include <LibraryVersions.h>
 
 #include <App/MaterialPy.h>
@@ -3722,7 +3721,7 @@ void Application::getVerboseCommonInfo(QTextStream& str, const std::map<std::str
     // report also the version numbers of the most important libraries in FreeCAD
     str << "Python " << PY_VERSION << ", ";
     str << "Qt " << QT_VERSION_STR << ", ";
-    str << "Coin " << COIN_VERSION << ", ";
+    str << "Coin " << fcCoin3dVersion << ", ";
     str << "Vtk " << fcVtkVersion << ", ";
     str << "boost " << BOOST_LIB_VERSION << ", ";
     str << "Eigen3 " << fcEigen3Version << ", ";

src/App/CMakeLists.txt

@@ -74,7 +74,6 @@ endif()
 include_directories(
     ${QtCore_INCLUDE_DIRS}
     ${QtXml_INCLUDE_DIRS}
-    ${Coin_INCLUDE_DIR}
 )
 list(APPEND FreeCADApp_LIBS
         ${QtCore_LIBRARIES}