Add wait_for_no_initializing_shards in yaml rest

Similar to #114641

Author: kingherc

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/mtermvectors/30_routing.yml

@@ -8,6 +8,10 @@ routing:
            index:
               number_of_shards: 5
 
+  - do:
+      cluster.health:
+        wait_for_no_initializing_shards: true
+
   - do:
       index:
         index:   test_1
@@ -51,6 +55,10 @@ requires routing:
             _routing:
               required: true
 
+  - do:
+      cluster.health:
+        wait_for_no_initializing_shards: true
+
   - do:
       index:
         index:   test_1

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/termvectors/20_issue7121.yml

@@ -14,6 +14,10 @@
                    type : "text"
                    term_vector : "with_positions_offsets"
 
+  - do:
+      cluster.health:
+        wait_for_no_initializing_shards: true
+
   - do:
       index:
         index: testidx

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/termvectors/30_realtime.yml

@@ -8,6 +8,10 @@
             index:
               refresh_interval: -1
 
+ - do:
+     cluster.health:
+       wait_for_no_initializing_shards: true
+
  - do:
       index:
           index:   test_1