fix(agents): never let self fall into the staleNodes filter (GH-2682) - #2689

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Handlers/Executor.cs(399,27): warning CS0419: Ambiguous reference in cref attribute: 'Build'. Assuming 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, System.Type)', but could have also matched other overloads including 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, Wolverine.Runtime.Handlers.IMessageHandler, Wolverine.Logging.IMessageTracker)'. [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Handlers/Executor.cs(64,65): warning CS0419: Ambiguous reference in cref attribute: 'Executor.Build'. Assuming 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, System.Type)', but could have also matched other overloads including 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, Wolverine.Runtime.Handlers.IMessageHandler, Wolverine.Logging.IMessageTracker)'. [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Agents/IAgent.cs(44,27): warning CS1066: The default value specified for parameter 'cancellationToken' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Middleware/TryCatchFinallyFrame.cs(177,17): warning CS8767: Nullability of reference types in type of parameter 'variable' of 'bool CatchBlockMethodVariables.TryFindVariableByName(Type dependency, string name, out Variable? variable)' doesn't match implicitly implemented member 'bool IMethodVariables.TryFindVariableByName(Type dependency, string name, out Variable? variable)' (possibly because of nullability attributes). [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Handlers/Executor.cs(399,27): warning CS0419: Ambiguous reference in cref attribute: 'Build'. Assuming 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, System.Type)', but could have also matched other overloads including 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, Wolverine.Runtime.Handlers.IMessageHandler, Wolverine.Logging.IMessageTracker)'. [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Handlers/Executor.cs(64,65): warning CS0419: Ambiguous reference in cref attribute: 'Executor.Build'. Assuming 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, System.Type)', but could have also matched other overloads including 'Wolverine.Runtime.Handlers.Executor.Build(Wolverine.Runtime.IWolverineRuntime, Microsoft.Extensions.ObjectPool.ObjectPool<Wolverine.Runtime.MessageContext>, Wolverine.Runtime.Handlers.HandlerGraph, Wolverine.Runtime.Handlers.IMessageHandler, Wolverine.Logging.IMessageTracker)'. [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Runtime/Agents/IAgent.cs(44,27): warning CS1066: The default value specified for parameter 'cancellationToken' will have no effect because it applies to a member that is used in contexts that do not allow optional arguments [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

/home/runner/work/wolverine/wolverine/src/Wolverine/Middleware/TryCatchFinallyFrame.cs(177,17): warning CS8767: Nullability of reference types in type of parameter 'variable' of 'bool CatchBlockMethodVariables.TryFindVariableByName(Type dependency, string name, out Variable? variable)' doesn't match implicitly implemented member 'bool IMethodVariables.TryFindVariableByName(Type dependency, string name, out Variable? variable)' (possibly because of nullability attributes). [/home/runner/work/wolverine/wolverine/src/Wolverine/Wolverine.csproj::TargetFramework=net9.0]

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.