Don't show index rebuild dialog when just upgrading index

tests/reference/coreIndex_LoadSave_tagsIndex.json

@@ -1,4 +1,8 @@
 {
+  "novelWriter.meta": {
+    "version": "0x020800a2",
+    "timestamp": "2025-10-05 17:06:58"
+  },
   "novelWriter.tagsIndex": {
     "bod": {"name": "Bod", "display": "Nobody Owens", "handle": "4c4f28287af27", "heading": "T0001", "class": "CHARACTER"},
     "main": {"name": "Main", "display": "Main", "handle": "2426c6f0ca922", "heading": "T0001", "class": "PLOT"},

tests/test_core/test_core_index.py

@@ -157,7 +157,7 @@ def testCoreIndex_LoadSave(qtbot, monkeypatch, prjLipsum, nwGUI, tstPaths):
 
     # Check File
     copyfile(projFile, testFile)
-    assert cmpFiles(testFile, compFile)
+    assert cmpFiles(testFile, compFile, ignoreLines=[3, 4])
 
     # Write an empty index file and load it
     projFile.write_text("{}", encoding="utf-8")