Validate ProtoIds in tests (#38745)

* Convert string literals to protoids in Content.Tests

* Convert string literals to protoids or consts in Content.IntegrationTests

* Fix linter failures
Tricksy static using misled me

Content.Tests/Shared/LocalizedDatasetPrototypeTest.cs

@@ -12,6 +12,8 @@ namespace Content.Tests.Shared;
 [TestOf(typeof(LocalizedDatasetPrototype))]
 public sealed class LocalizedDatasetPrototypeTest : ContentUnitTest
 {
+    private const string TestDatasetId = "Test";
+
     private IPrototypeManager _prototypeManager;
 
     [OneTimeSetUp]
@@ -24,9 +26,9 @@ public sealed class LocalizedDatasetPrototypeTest : ContentUnitTest
         _prototypeManager.ResolveResults();
     }
 
-    private const string TestPrototypes = @"
+    private const string TestPrototypes = $@"
 - type: localizedDataset
-  id: Test
+  id: {TestDatasetId}
   values:
     prefix: test-dataset-
     count: 4
@@ -35,7 +37,7 @@ public sealed class LocalizedDatasetPrototypeTest : ContentUnitTest
     [Test]
     public void LocalizedDatasetTest()
     {
-        var testPrototype = _prototypeManager.Index<LocalizedDatasetPrototype>("Test");
+        var testPrototype = _prototypeManager.Index<LocalizedDatasetPrototype>(TestDatasetId);
         var values = new ValueList<string>();
         foreach (var value in testPrototype.Values)
         {