Align nullabilty of PhysicalPath property with IFileInfo

Author: ronaldbarendse

src/Umbraco.StorageProviders.AzureBlob/AzureBlobItemInfo.cs

@@ -72,7 +72,7 @@ private AzureBlobItemInfo(BlobClient blobClient)
     public string Name { get; }
 
     /// <inheritdoc />
-    public string PhysicalPath => null!;
+    public string? PhysicalPath => null;
 
     /// <inheritdoc />
     public Stream CreateReadStream() => _blobClient.OpenRead();

src/Umbraco.StorageProviders.AzureBlob/AzureBlobPrefixInfo.cs

@@ -36,7 +36,7 @@ public AzureBlobPrefixInfo(string prefix)
     public string Name { get; }
 
     /// <inheritdoc />
-    public string PhysicalPath => null!;
+    public string? PhysicalPath => null;
 
     /// <inheritdoc />
     public Stream CreateReadStream() => throw new InvalidOperationException();