test(sync): skip testMovedWithError suffix VFS row when plugin missing

Gate the Vfs::WithSuffix data row on isVfsPluginAvailable, mirroring the
existing Vfs::WindowsCfApi handling, so the test skips instead of failing
when the suffix plugin is not built.

Assisted-by: Claude Code:claude-opus-4-8
Signed-off-by: Camila Ayres <hello@camilasan.com>

Author: camilasan

test/testsyncmove.cpp

@@ -966,7 +966,11 @@ private slots:
         QTest::addColumn<Vfs::Mode>("vfsMode");
 
         QTest::newRow("Vfs::Off") << Vfs::Off;
-        QTest::newRow("Vfs::WithSuffix") << Vfs::WithSuffix;
+        if (isVfsPluginAvailable(Vfs::WithSuffix)) {
+            QTest::newRow("Vfs::WithSuffix") << Vfs::WithSuffix;
+        } else {
+            QWARN("Skipping Vfs::WithSuffix");
+        }
 #ifdef Q_OS_WIN32
         if (isVfsPluginAvailable(Vfs::WindowsCfApi))
         {