Fix yml test {p0=indices.delete_index_template/10_basic} is flaky (#15162)

* Fix yml test {p0=indices.delete_index_template/10_basic} is flaky

Signed-off-by: Gao Binlong <gbinlong@amazon.com>

* Fix warning message

Signed-off-by: Gao Binlong <gbinlong@amazon.com>

---------

Signed-off-by: Gao Binlong <gbinlong@amazon.com>

Author: gaobinlong

rest-api-spec/src/main/resources/rest-api-spec/test/indices.delete_index_template/10_basic.yml

@@ -1,5 +1,9 @@
 setup:
+  - skip:
+      features: allowed_warnings
   - do:
+      allowed_warnings:
+        - "index template [test_template_1] has index patterns [test-*] matching patterns from existing older templates [global] with patterns (global => [*]); this template [test_template_1] will take precedence during new index creation"
       indices.put_index_template:
         name: test_template_1
         body:
@@ -11,6 +15,8 @@ setup:
           "priority": 50
 
   - do:
+      allowed_warnings:
+        - "index template [test_template_2] has index patterns [test-*] matching patterns from existing older templates [global] with patterns (global => [*]); this template [test_template_2] will take precedence during new index creation"
       indices.put_index_template:
         name: test_template_2
         body: