Saved objects search does not escape hyphens

[marius-dr]

Kibana version: 6.7.0

Describe the bug:
If you try to search for a saved object that contains a hyphen it doesn't find it if you use the exact name. It doesn't matter if you try and escape it with a \ or with " around the whole string. The query that gets to to the _find endpoint of the saved_object_api is the same every time.

Steps to reproduce:

1. Create an index pattern with a - in it. For example "metricbeat-*"
2. Serach for it in the Saved objects page with any of the following terms: metricbeat-* , metricbeat\-* "metricbeat-*"

The requests looks like this in all the cases:
/api/saved_objects/_find?search=metricbeat-**&per_page=20&page=1&fields=title&fields=id&search_fields=title&type=ind

[elasticmachine]

Pinging @elastic/kibana-platform

[nreese]

Closing, duplicate of #5734