Dependency update / fixes / skrungle bungle (#23745)

* Give .props files 2-space indents.

* Move to Central Package Management.

Allows us to store NuGet package versions all in one place. Yay!

* Update NuGet packages and fix code for changes.

Notable:

Changes to ILVerify.
Npgsql doesn't need hacks for inet anymore, now we need hacks to make the old code work with this new reality.
NUnit's analyzers are already complaining and I didn't even update it to 4.x yet.
TerraFX changed to GetLastSystemError so error handling had to be changed.
Buncha APIs have more NRT annotations.

* Remove dotnet-eng NuGet package source.

I genuinely don't know what this was for, and Central Package Management starts throwing warnings about it, so YEET.

* Remove Robust.Physics project.

Never used.

* Remove erroneous NVorbis reference.

Should be VorbisPizza and otherwise wasn't used.

* Sandbox fixes

* Remove unused unit test package references.

Castle.Core and NUnit.ConsoleRunner.

* Update NUnit to 4.0.1

This requires replacing all the old assertion methods because they removed them 🥲

* Oh so that's what dotnet-eng was used for. Yeah ok that makes sense.

* Add Robust.Analyzers.Test

* Update submodule

* commit to re-run CI

Content.IntegrationTests/Tests/Minds/GhostRoleTests.cs

@@ -60,7 +60,7 @@ public sealed class GhostRoleTests
         Assert.That(session.AttachedEntity, Is.EqualTo(originalMob));
         var originalMind = entMan.GetComponent<MindComponent>(originalMindId);
         Assert.That(originalMind.OwnedEntity, Is.EqualTo(originalMob));
-        Assert.Null(originalMind.VisitingEntity);
+        Assert.That(originalMind.VisitingEntity, Is.Null);
 
         // Use the ghost command
         conHost.ExecuteCommand("ghost");
@@ -90,11 +90,11 @@ public sealed class GhostRoleTests
         Assert.That(newMindId, Is.Not.EqualTo(originalMindId));
         Assert.That(session.AttachedEntity, Is.EqualTo(ghostRole));
         Assert.That(newMind.OwnedEntity, Is.EqualTo(ghostRole));
-        Assert.Null(newMind.VisitingEntity);
+        Assert.That(newMind.VisitingEntity, Is.Null);
 
         // Original mind should be unaffected, but the ghost will have deleted itself.
         Assert.That(originalMind.OwnedEntity, Is.EqualTo(originalMob));
-        Assert.Null(originalMind.VisitingEntity);
+        Assert.That(originalMind.VisitingEntity, Is.Null);
         Assert.That(entMan.Deleted(ghost));
 
         // Ghost again.
@@ -113,11 +113,11 @@ public sealed class GhostRoleTests
         await pair.RunTicksSync(10);
         Assert.That(session.AttachedEntity, Is.EqualTo(originalMob));
         Assert.That(originalMind.OwnedEntity, Is.EqualTo(originalMob));
-        Assert.Null(originalMind.VisitingEntity);
+        Assert.That(originalMind.VisitingEntity, Is.Null);
 
         // the ghost-role mind is unaffected, though the ghost will have deleted itself
         Assert.That(newMind.OwnedEntity, Is.EqualTo(ghostRole));
-        Assert.Null(newMind.VisitingEntity);
+        Assert.That(newMind.VisitingEntity, Is.Null);
         Assert.That(entMan.Deleted(otherGhost));
 
         await pair.CleanReturnAsync();