QmlPreview: workaround for not starting preview

In the case of absolute path, do not try wrongly calculated
candidates in case of a parent dir and a sub dir having the
same name.
A directory with UntitledProject68/UntitledProject68/Screen01.qml,
asking for parent UntitledProject68 listed the subdirectory content instead of the parent directory.

Task-number: QDS-13292
Change-Id: I6edb61957200b10f9465ad2eaeefeee533ac2375
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/fileinprojectfinder.cpp

@@ -191,6 +191,11 @@ bool FileInProjectFinder::findFileOrDirectory(const FilePath &originalPath, File
             directoryHandler(node->children.keys(), origLength);
             qCDebug(finderLog) << "FileInProjectFinder: found virtual directory" << originalPath
                                << "in mapped paths";
+        }
+    }
+
+    if (originalPath == m_projectDir) {
+        if (checkPath(originalPath, originalPath.toFSPathString().length(), fileHandler, directoryHandler)) {
             return true;
         }
     }