Add notes about binary data in result

Author: sfodagain

samples/service_clients/commands/commands-sandbox/README.md

@@ -440,6 +440,9 @@ You can also provide a result with the update:
 update-command-execution <execution-id> IN_PROGRESS result=battery_ok:true;message:"doing something"
 ```
 
+> [!NOTE]
+> You can also pass binary data in the result field using the CommandExecutionResult::Bin member, which is not supported in this sample.
+
 Then this AWS CLI command
 ```shell
 aws iot get-command-execution --target-arn "<thing ARN>" --execution-id <IoT command execution ID> --include-result

samples/service_clients/commands/commands-sandbox/main.cpp

@@ -144,6 +144,8 @@ static Aws::Crt::String s_extractValue(std::istringstream &stream)
 static Aws::Iotcommands::CommandExecutionResult s_makeResultEntry(const Aws::Crt::String &value)
 {
     Aws::Iotcommands::CommandExecutionResult entry;
+    // NOTE: CommandExecutionResult also supports binary data via the `Bin` member, which is not demonstrated in this
+    // sample.
     if (value == "true" || value == "false")
     {
         entry.B = (value == "true");