chore(examples): fix warnings

Author: sd-st

examples/MessagesExample.Bedrock/Program.cs

@@ -32,8 +32,8 @@ await AnthropicBedrockCredentialsHelper.FromEnv().ConfigureAwait(false)
 var message = string.Join(
     "",
     response
-        .Content.Where(message => message.Value is TextBlock)
-        .Select(message => message.Value as TextBlock)
+        .Content.Select(message => message.Value)
+        .OfType<TextBlock>()
         .Select((textBlock) => textBlock.Text)
 );
 

examples/MessagesExample.Vertex/Program.cs

@@ -43,8 +43,8 @@ ServiceAccount JSON
 var message = string.Join(
     "",
     response
-        .Content.Where(message => message.Value is TextBlock)
-        .Select(message => message.Value as TextBlock)
+        .Content.Select(message => message.Value)
+        .OfType<TextBlock>()
         .Select((textBlock) => textBlock.Text)
 );