[ML] Wait for ML indices in rolling upgrade tests (elastic#30615)

Author: davidkyle

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/30_ml_jobs_crud.yml

@@ -110,6 +110,13 @@ setup:
       xpack.ml.close_job:
         job_id: mixed-cluster-job
 
+# Wait for indices to be fully allocated before
+# killing the node
+  - do:
+     cluster.health:
+       index: [".ml-state", ".ml-anomalies-shared"]
+       wait_for_status: green
+
 ---
 "Test get job with rules":
 

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/30_ml_jobs_crud.yml

@@ -49,6 +49,13 @@
         job_id: old-cluster-job
   - match: { count: 1 }
 
+# Wait for indices to be fully allocated before
+# killing the node
+  - do:
+     cluster.health:
+       index: [".ml-state", ".ml-anomalies-shared"]
+       wait_for_status: green
+
 ---
 "Put job on the old cluster with the default model memory limit and post some data":
   - do:
@@ -96,6 +103,13 @@
         job_id: no-model-memory-limit-job
   - match: { count: 201 }
 
+# Wait for indices to be fully allocated before
+# killing the node
+  - do:
+     cluster.health:
+       index: [".ml-state", ".ml-anomalies-shared"]
+       wait_for_status: green
+
 ---
 "Put job with empty strings in the configuration":
   - do: