Add flags to give permissions to write to any dataset and namespace (#…

…157897)

Add flags to give permissions to reroute events from an input package to
other datastreams with the same type but different dataset and
namespace.

```
elasticsearch.dynamic_dataset: true
elasticsearch.dynamic_namespace: true,
```

x-pack/plugins/fleet/common/services/policy_template.test.ts

@@ -229,6 +229,10 @@ describe('getNormalizedDataStreams', () => {
       {
         type: 'foo',
         dataset: 'nginx.bar',
+        elasticsearch: {
+          dynamic_dataset: true,
+          dynamic_namespace: true,
+        },
         title: expect.any(String),
         release: 'ga',
         package: 'nginx',

x-pack/plugins/fleet/common/services/policy_template.ts

@@ -87,7 +87,7 @@ export const getNormalizedDataStreams = (
       release: packageInfo.release || 'ga',
       package: packageInfo.name,
       path: packageInfo.name,
-      elasticsearch: packageInfo.elasticsearch,
+      elasticsearch: packageInfo.elasticsearch || {},
       streams: [
         {
           input: policyTemplate.input,
@@ -100,6 +100,16 @@ export const getNormalizedDataStreams = (
       ],
     };
 
+    if (packageInfo.type === 'input') {
+      dataStream.elasticsearch = {
+        ...dataStream.elasticsearch,
+        ...{
+          dynamic_dataset: true,
+          dynamic_namespace: true,
+        },
+      };
+    }
+
     return dataStream;
   });
 };