Core: Fixed a bug where an empty document disappears (#20554)

* Core: Fixed a bug where an empty document disappears

Created a flag named autoCreated to distinguish an autoCreated
document created in the startup from a manually document.
Implemented a setter and a getter for this new flag.
Added a codition that verifies if a document is autoCreated
when opening another document to close it in the correct case.
Implemented unit tests for theses cases. Fixes #19868.

Signed-off-by: João Neves <joao.antonio.neves@tecnico.ulisboa.pt>

* Tests: Fix failing auto-created document tests

Signed-off-by: João Neves <joao.antonio.neves@tecnico.ulisboa.pt>

* Tests: moved created tests to the existing Document test framework.

Signed-off-by: João Neves <joao.antonio.neves@tecnico.ulisboa.pt>

---------

Signed-off-by: João Neves <joao.antonio.neves@tecnico.ulisboa.pt>

src/App/Document.cpp

@@ -840,6 +840,7 @@ Document::Document(const char* documentName)
     // So, we must increment only if the interpreter gets a reference.
     // Remark: We force the document Python object to own the DocumentPy instance, thus we don't
     // have to care about ref counting any more.
+    setAutoCreated(false);
     d = new DocumentP;
     Base::PyGILStateLocker lock;
     d->DocumentPythonObject = Py::Object(new DocumentPy(this), true);
@@ -2505,6 +2506,14 @@ std::string Document::getFullName() const
     return myName;
 }
 
+void Document::setAutoCreated(bool value) {
+    autoCreated = value;
+}
+
+bool Document::isAutoCreated() const {
+    return autoCreated;
+}
+
 const char* Document::getProgramVersion() const
 {
     return d->programVersion.c_str();