Utils: Make Utils::withTildeHomePath a FilePath member

Gets .osType() right in remote cases.

Change-Id: I6397996062d976d7db690c5729dd4faa1f459563
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/projectexplorer/sessionmodel.cpp

@@ -84,7 +84,7 @@ QStringList pathsToBaseNames(const QStringList &paths)
 QStringList pathsWithTildeHomePath(const QStringList &paths)
 {
     return Utils::transform(paths, [](const QString &path) {
-        return Utils::withTildeHomePath(QDir::toNativeSeparators(path));
+        return FilePath::fromString(path).withTildeHomePath();
     });
 }