chore: fix expected for svelte 5

packages/language-server/test/plugins/typescript/features/diagnostics/fixtures/svelte-element-error/expected_svelte_5.json

@@ -3,7 +3,7 @@
         "range": { "start": { "line": 4, "character": 0 }, "end": { "line": 4, "character": 0 } },
         "severity": 1,
         "source": "ts",
-        "message": "`<svelte:element>` must have a 'this' attribute",
+        "message": "`<svelte:element>` must have a 'this' attribute with a value",
         "code": -1
     }
 ]