Java issues batch 8 (#2959)

* [877] ngram and edge tokenizer optional values

* [880] _shards optional because of wait_for_completion

* [881] added missing allow_custom_routing

* [883] action and name optional next_step

* both steps mandatory in move to step request

(cherry picked from commit 3b1143a)

Author: l-trotta

Diff for: output/openapi/elasticsearch-openapi.json

@@ -89,7 +89,8 @@ export class IndicesResponseBase extends AcknowledgedResponseBase {
 }
 
 export class ShardsOperationResponseBase {
-  _shards: ShardStatistics
+  // _shards is always returned, but not when wait_for_completion is false in the request
+  _shards?: ShardStatistics
 }
 
 export class CustomResponseBuilderBase {}

Diff for: output/openapi/elasticsearch-serverless-openapi.json

@@ -48,8 +48,8 @@ export class ClassicTokenizer extends TokenizerBase {
 export class EdgeNGramTokenizer extends TokenizerBase {
   type: 'edge_ngram'
   custom_token_chars?: string
-  max_gram: integer
-  min_gram: integer
+  max_gram?: integer
+  min_gram?: integer
   /**
    * @server_default []
    */
@@ -84,8 +84,8 @@ export class LowercaseTokenizer extends TokenizerBase {
 export class NGramTokenizer extends TokenizerBase {
   type: 'ngram'
   custom_token_chars?: string
-  max_gram: integer
-  min_gram: integer
+  max_gram?: integer
+  min_gram?: integer
   /**
    * @server_default []
    */