PLANET-6235: Update ElasticPress to 4.5

[lithrel]

Ref: https://jira.greenpeace.org/browse/PLANET-6235

Changelog: https://github.com/10up/ElasticPress/blob/develop/CHANGELOG.md (from 3.5.6)

Some commands have changed. We only use indexation, and the old command is deprecated but not removed so we can apply those changes after update:

Old Command	New Command
wp elasticpress index	wp elasticpress sync
wp elasticpress get-cluster-indexes	wp elasticpress get-cluster-indices
wp elasticpress get-indexes	wp elasticpress get-indices
wp elasticpress clear-index	wp elasticpress clear-sync
wp elasticpress get-indexing-status	wp elasticpress get-ongoing-sync-status
wp elasticpress get-last-cli-index	wp elasticpress get-last-cli-sync
wp elasticpress stop-indexing	wp elasticpress stop-sync

Some filters have changed, but we don't use any of those:

Old Filter	New Filter
ep_formatted_args_query	ep_post_formatted_args_query
ep_match_phrase_boost	ep_post_match_phrase_boost
ep_match_boost	ep_post_match_boost
ep_fuzziness_arg	ep_post_fuzziness_arg
ep_match_fuzziness	ep_post_match_fuzziness
ep_match_cross_fields_boost	ep_post_match_cross_fields_boost

Our current installation of Elasticpress With WPML doesn't allow for language specific search. We should open a ticket to try the plugin dedicated to this https://wpml.org/documentation/plugins-compatibility/using-elasticpress-on-your-multilingual-site/ (using the master branch instead of the release).

[comzeradd]

👍

I think we only use the index command on the two development environments.