Use internal reader when building SecurityIndexReaderWrapper filter query

[jfreden]

Relates: https://github.com/elastic/elasticsearch/issues/112130

When using wildcards to match fields in a multi_match query within a DLS query in a role, the fields are not properly expanded because there is no index reader that can read the index mapping to expand the wildcards.

This happens because a searcher is needed to read the mappings to figure out what fields are available for an index.

The searcher is expected to be supplied by the Security plugin when it calls IndexModule::setReaderWrapper to override the IndexReader factory. Currently it passes null for the searcher parameter, which makes expansions of wildcard fields impossible.

This PR changes that by providing the reader that wrapped by SecurityIndexReaderWrapper when the filter query is built to be able to resolve wildcard fields.