Consider whether ES STARTSWITH/LIKE/ILIKE should work with prefix and ecm:name

According to NXP-18228 / NXP-18955 , it is wished that ES STARTSWITH/LIKE/ILIKE with "prefix%" syntax works as with VCS. This is currently not the case for the ecm:name field.
In LTS 2021, the following error is logged:

{"error":{"root_cause":[{"type":"query_shard_exception","reason": "failed to create query: Can only use phrase prefix queries on text fields - not on [ecm:name] which is of type [keyword]" ,"index_uuid":"eRwnq68CTLC8jmo4RQ2t9Q","index":"nuxeo"}],"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":[{"shard":0,"index":"nuxeo","node":"Acb14Q8eQzer75-JvOMiXg","reason":{"type":"query_shard_exception","reason":"failed to create query: Can only use phrase prefix queries on text fields - not on [ecm:name] which is of type [keyword]","index_uuid":"eRwnq68CTLC8jmo4RQ2t9Q","index":"nuxeo","caused_by":{"type":"illegal_argument_exception","reason":"Can only use phrase prefix queries on text fields - not on [ecm:name] which is of type [keyword]"}}}]},"status":400}

How to reproduce:

• Install Nuxeo LTS 2019 or LTS2021 with all hotfixes and nuxeo-showcase-content and nuxeo-web-ui
• include in nuxeo.conf:

  elasticsearch.override.pageproviders=nxql_search

• boot Nuxeo
• invoke NXQL Search with the query: (CONTAINS type)

  SELECT * FROM Document WHERE dc:title LIKE "%Lorem%"

  => returns the Lorem ipsum note

• invoke NXQL Search with the query: (STARTSWITH type)

  SELECT * FROM Document WHERE dc:title LIKE "Lorem%"

  => returns the Lorem ipsum note

• invoke NXQL Search with the query: (CONTAINS type)

  SELECT * FROM Document WHERE ecm:name LIKE "%Lorem%"

  => returns the Lorem ipsum note

• invoke NXQL Search with the query: (STARTSWITH type)

  SELECT * FROM Document WHERE ecm:name LIKE "Lorem%"

  => DOES NOT RETURN ANYTHING => REPRODUCED
  => In LTS 2021, error HTTP 400 in server.log with "reason": "failed to create query: Can only use phrase prefix queries on text fields - not on [ecm:name] which is of type [keyword]"

Commenting in nuxeo.conf:

elasticsearch.override.pageproviders=nxql_search

makes the query

SELECT * FROM Document WHERE ecm:name LIKE "Lorem%"

returning the Lorem ipsum note

The request is to consider whether Elasticsearch should behave in the same way than the DB in the case of the ecm:name and eventually fix the current behavior