[ML] Mute data frame analytics BWC tests (#68269)

Until #68099 is backported to 7.x.

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/90_ml_data_frame_analytics_crud.yml

@@ -1,3 +1,8 @@
+setup:
+  - skip:
+      version: "all"
+      reason:  "Until backport of https://github.com/elastic/elasticsearch/pull/68099"
+
 ---
 "Get old outlier_detection job":
 

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/90_ml_data_frame_analytics_crud.yml

@@ -1,4 +1,7 @@
 setup:
+  - skip:
+      version: "all"
+      reason:  "Until backport of https://github.com/elastic/elasticsearch/pull/68099"
 
   - do:
       index:

x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/90_ml_data_frame_analytics_crud.yml

@@ -1,3 +1,8 @@
+setup:
+  - skip:
+      version: "all"
+      reason:  "Until backport of https://github.com/elastic/elasticsearch/pull/68099"
+
 ---
 "Get old cluster outlier_detection job":