Add link from issue contacts to issues list

Related to #361613 (closed)

This MR removes the inconsistent bold styling from contacts in the sidebar, and links them to the group issue list filtered for the selected contact.

I've also taken the opportunity to remove some redundant params from the querystring we're using to link from the contacts list and organizations list.

before	after

Recreation steps

https://docs.gitlab.com/ee/user/crm/

1. Enable :customer_relations and :contacts_automcomplete feature flags
2. Enable customer relations in a root group's settings
3. Create a contact (if your database hasn't already been seeded with some)
4. Add one or more contacts to an issue (using /add_contacts quick action)
5. Ensure clicking the contacts links to the group issues list (filtered for the selected contact)