Add some leniency when reading index version (#98742)

Serverless already has some indexes that were created with an 8.11 version. So allow that when reading index metadata here.

server/src/main/java/org/elasticsearch/index/engine/Engine.java

@@ -155,7 +155,7 @@ public abstract class Engine implements Closeable {
         if (esVersion.contains(".")) {
             // backwards-compatible Version-style
             org.elasticsearch.Version v = org.elasticsearch.Version.fromString(esVersion);
-            assert v.before(org.elasticsearch.Version.V_8_11_0);
+            assert v.onOrBefore(org.elasticsearch.Version.V_8_11_0);
             return IndexVersion.fromId(v.id);
         } else {
             return IndexVersion.fromId(Integer.parseInt(esVersion));