Exposes getter for part converters in FormHttpMessageConverter

Closes gh-25817

spring-web/src/main/java/org/springframework/http/converter/FormHttpMessageConverter.java

@@ -231,6 +231,14 @@ public class FormHttpMessageConverter implements HttpMessageConverter<MultiValue
 		this.partConverters = partConverters;
 	}
 
+	/**
+	 * Return the {@link #setPartConverters configured} converters for MIME parts.
+	 * @since 5.3
+	 */
+	public List<HttpMessageConverter<?>> getPartConverters() {
+		return Collections.unmodifiableList(this.partConverters);
+	}
+
 	/**
 	 * Add a message body converter. Such a converter is used to convert objects
 	 * to MIME parts.