Revert "[TEST] Mute index synced flush rest tests"

The BWC issue was fixed.
This reverts commit f8830b7b43.

rest-api-spec/src/main/resources/rest-api-spec/test/cat.shards/10_basic.yml

@@ -80,10 +80,6 @@
                $/
 ---
 "Test cat shards output":
-  - skip:
-      # The BWC logic for released 6.0 and 6.1 versions is wrong
-      version: "all"
-      reason:  "AwaitsFix'ing, see elasticsearch #29162"
 
   - do:
       cat.shards: {}

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

@@ -1,10 +1,5 @@
 ---
 "Index synced flush rest test":
-    - skip:
-        # The BWC logic for released 6.0 and 6.1 versions is wrong
-        version: "all"
-        reason:  "AwaitsFix'ing, see elasticsearch #29162"
-
     - do:
        indices.create:
           index: testing