Ensure class resource stream is closed in ResourceUtils (#116437)

* Ensure class resource stream is closed in ResourceUtils

This ensures that `ResourceUtils.loadResource` closes the resource stream when reading all bytes.

* Update docs/changelog/116437.yaml

Author: dakrone

docs/changelog/116437.yaml

@@ -0,0 +1,5 @@
+pr: 116437
+summary: Ensure class resource stream is closed in `ResourceUtils`
+area: Indices APIs
+type: enhancement
+issues: []

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/template/ResourceUtils.java

@@ -35,11 +35,12 @@ static byte[] loadVersionedResourceUTF8(
     }
 
     public static String loadResource(Class<?> clazz, String name) throws IOException {
-        InputStream is = clazz.getResourceAsStream(name);
-        if (is == null) {
-            throw new IOException("Resource [" + name + "] not found in classpath.");
+        try (InputStream is = clazz.getResourceAsStream(name)) {
+            if (is == null) {
+                throw new IOException("Resource [" + name + "] not found in classpath.");
+            }
+            return new String(is.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8);
         }
-        return new String(is.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8);
     }
 
 }