Fix nullability annotations in ProtocolDiagnosticNupkgCopiedEvent and PublicAPI files

Agent-Logs-Url: https://github.com/NuGet/NuGet.Client/sessions/99e74a70-9115-4726-adbb-4b262f30d6da

Co-authored-by: nkolev92 <2878341+nkolev92@users.noreply.github.com>

Author: Copilot

src/NuGet.Core/NuGet.Protocol/Events/ProtocolDiagnosticNupkgCopiedEvent.cs

@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 namespace NuGet.Protocol.Events
 {
     public sealed class ProtocolDiagnosticNupkgCopiedEvent
@@ -13,7 +11,7 @@ public sealed class ProtocolDiagnosticNupkgCopiedEvent
         /// <summary>
         /// Gets the package ID of the copied nupkg, or <see langword="null"/> if not available.
         /// </summary>
-        public string PackageId { get; }
+        public string? PackageId { get; }
 
         public ProtocolDiagnosticNupkgCopiedEvent(
             string source,
@@ -25,7 +23,7 @@ public ProtocolDiagnosticNupkgCopiedEvent(
         public ProtocolDiagnosticNupkgCopiedEvent(
             string source,
             long fileSize,
-            string packageId)
+            string? packageId)
         {
             Source = source;
             FileSize = fileSize;

src/NuGet.Core/NuGet.Protocol/PublicAPI/net472/PublicAPI.Shipped.txt

@@ -378,8 +378,8 @@ NuGet.Protocol.Events.ProtocolDiagnosticHttpEventBase.IsRetry.get -> bool
 ~NuGet.Protocol.Events.ProtocolDiagnosticHttpEventBase.Url.get -> System.Uri
 NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent
 NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.FileSize.get -> long
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string source, long fileSize) -> void
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.Source.get -> string
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string! source, long fileSize) -> void
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.Source.get -> string!
 NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent
 NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent.Duration.get -> System.TimeSpan
 ~NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent.Method.get -> string

src/NuGet.Core/NuGet.Protocol/PublicAPI/net472/PublicAPI.Unshipped.txt

@@ -1,3 +1,3 @@
 #nullable enable
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.PackageId.get -> string
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string source, long fileSize, string packageId) -> void
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.PackageId.get -> string?
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string! source, long fileSize, string? packageId) -> void

src/NuGet.Core/NuGet.Protocol/PublicAPI/net8.0/PublicAPI.Shipped.txt

@@ -378,8 +378,8 @@ NuGet.Protocol.Events.ProtocolDiagnosticHttpEventBase.IsRetry.get -> bool
 ~NuGet.Protocol.Events.ProtocolDiagnosticHttpEventBase.Url.get -> System.Uri
 NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent
 NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.FileSize.get -> long
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string source, long fileSize) -> void
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.Source.get -> string
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string! source, long fileSize) -> void
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.Source.get -> string!
 NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent
 NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent.Duration.get -> System.TimeSpan
 ~NuGet.Protocol.Events.ProtocolDiagnosticResourceEvent.Method.get -> string

src/NuGet.Core/NuGet.Protocol/PublicAPI/net8.0/PublicAPI.Unshipped.txt

@@ -1,3 +1,3 @@
 #nullable enable
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.PackageId.get -> string
-~NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string source, long fileSize, string packageId) -> void
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.PackageId.get -> string?
+NuGet.Protocol.Events.ProtocolDiagnosticNupkgCopiedEvent.ProtocolDiagnosticNupkgCopiedEvent(string! source, long fileSize, string? packageId) -> void