[TEST] Don't use replicas to stabelize assertion.

This test asserts that the first recovery result is of type SNAPSHOT.
This assertion might not be true depending on the rendering order if
a replica is recovered quick enough. This commit disables replicas and
their recovery since it's not the purpose of this test.

rest-api-spec/src/main/resources/rest-api-spec/test/snapshot.restore/10_basic.yaml

@@ -15,11 +15,11 @@ setup:
         body:
           settings:
             number_of_shards:   1
-            number_of_replicas: 1
+            number_of_replicas: 0
 
   - do:
       cluster.health:
-        wait_for_status: yellow
+        wait_for_status: green
 
 ---
 "Create a snapshot and then restore it":