Update supported version for the wait_for_completion parameter in open&clone&shrink&split APIs (opensearch-project#12819)

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

Author: gaobinlong

rest-api-spec/src/main/resources/rest-api-spec/test/indices.clone/40_wait_for_completion.yml

@@ -4,8 +4,8 @@
   # will return a task immediately and the clone operation will run in background.
 
   - skip:
-      version: " - 2.99.99"
-      reason: "only available in 3.0+"
+      version: " - 2.6.99"
+      reason: "wait_for_completion was introduced in 2.7.0"
       features: allowed_warnings
 
   - do:

rest-api-spec/src/main/resources/rest-api-spec/test/indices.open/30_wait_for_completion.yml

@@ -4,8 +4,8 @@
   # will return a task immediately and the open operation will run in background.
 
   - skip:
-      version: " - 2.99.99"
-      reason: "only available in 3.0+"
+      version: " - 2.6.99"
+      reason: "wait_for_completion was introduced in 2.7.0"
       features: allowed_warnings
 
   - do:

rest-api-spec/src/main/resources/rest-api-spec/test/indices.shrink/50_wait_for_completion.yml

@@ -4,8 +4,8 @@
   # will return a task immediately and the shrink operation will run in background.
 
   - skip:
-      version: " - 2.99.99"
-      reason: "only available in 3.0+"
+      version: " - 2.6.99"
+      reason: "wait_for_completion was introduced in 2.7.0"
       features: allowed_warnings
 
   - do:

rest-api-spec/src/main/resources/rest-api-spec/test/indices.split/40_wait_for_completion.yml

@@ -4,8 +4,8 @@
   # will return a task immediately and the split operation will run in background.
 
   - skip:
-      version: " - 2.99.99"
-      reason: "only available in 3.0+"
+      version: " - 2.6.99"
+      reason: "wait_for_completion was introduced in 2.7.0"
       features: allowed_warnings
 
   - do: