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/Actions/ActionsAddedTest.cs

@@ -29,7 +29,7 @@ public sealed class ActionsAddedTest
         var cActionSystem = client.System<SharedActionsSystem>();
 
         // Dummy ticker is disabled - client should be in control of a normal mob.
-        Assert.NotNull(serverSession.AttachedEntity);
+        Assert.That(serverSession.AttachedEntity, Is.Not.Null);
         var serverEnt = serverSession.AttachedEntity!.Value;
         var clientEnt = clientSession!.AttachedEntity!.Value;
         Assert.That(sEntMan.EntityExists(serverEnt));
@@ -57,8 +57,8 @@ public sealed class ActionsAddedTest
         var sAct = sActions[0].Comp;
         var cAct = cActions[0].Comp;
 
-        Assert.NotNull(sAct);
-        Assert.NotNull(cAct);
+        Assert.That(sAct, Is.Not.Null);
+        Assert.That(cAct, Is.Not.Null);
 
         // Finally, these two actions are not the same object
         // required, because integration tests do not respect the [NonSerialized] attribute and will simply events by reference.