Corrected indentation of of collection YML section

From:
~~~
  spec:
    collection:
    logs:
      type: "vector"
      vector: {}
~~~

To:
~~~
  spec:
    collection:
      logs:
        type: "vector"
        vector: {}
~~~

Author: dhgautam99

modules/cluster-logging-vector-tech-preview.adoc

@@ -58,9 +58,9 @@ $ oc -n openshift-logging edit ClusterLogging instance
       logging.openshift.io/preview-vector-collector: enabled
   spec:
     collection:
-    logs:
-      type: "vector"
-      vector: {}
+      logs:
+        type: "vector"
+        vector: {}
 ----
 
 [role="_additional-resources"]