insights: "click in to diff" feature on all-repo insights handles filter special characters incorrectly

Created by: Joelkw

Loom walkthrough

We handle filters – almost! If a user has regex characters in their filter, we're escaping them to pass through the url (or something) but we need to un-escape them when they land in the search query.

So a filter like sourcegraph/sourcegraph$ ends up being passed in as repo:sourcegraph/sourcegraph\$ but it needs to not have the \ to work.