Adjust shard limit applied version after backport (#71787)

After #71760 has been backported, we can adjust the version for when to
apply the new shard limit.

Author: henningandersen

x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/action/TransportMountSearchableSnapshotAction.java

@@ -154,8 +154,7 @@ private static Settings buildIndexSettings(
                 .put(DiskThresholdDecider.SETTING_IGNORE_DISK_WATERMARKS.getKey(), true);
 
             // we cannot apply this setting during rolling upgrade.
-            // todo: update version after backport
-            if (minNodeVersion.onOrAfter(Version.V_8_0_0)) {
+            if (minNodeVersion.onOrAfter(Version.V_7_13_0)) {
                 settings.put(ShardLimitValidator.INDEX_SETTING_SHARD_LIMIT_GROUP.getKey(), ShardLimitValidator.FROZEN_GROUP);
             }
         }