Enabling "Wildcard at the start" breaks lucene requests

[dmitriim]

Steps to replicate:

1. Assuming you have global search configured to use elastic search
2. Go to /admin/settings.php?section=elasticsettings and enable "Wildcard at the start"
3. Search for title:news

Error: Error executing query in search engine: Failed to parse query [*title:news]

[dmitriim]

Some tips for debugging/fixing from @mattporritt :

Also some depending on the index field type wildcards might not be supported.
The way I debug this is by using curl to send json queries directly to elastic
that way you can take Moodle completely out of it.
and see what the JSON looks like exaclt that you are sending and then see the complete response elastic sends back
once you've got the json doing what you want, you can then concentrate on getting moodle constructing it correctly
then you can write a unit test to cover it
it's a bit of a journey figuring out how to structure a query that elastic likes and does what you want