Issue Analytics - Add missing filters to Enhanced Issue Analytics chart

Problem

Due to limited filter sets in the issuesCompletedCount and issueCount metrics, we had to exclude the missing filters from the filtered search bar behind the issues_completed_analytics_feature_flag feature flag.

Solution

1. Stop excluding the the following filters in filtered_search_issues_analytics.js:
   1. epic
   2. my-reaction
   3. weight
2. Stop hiding the != operator from the dropdowns in filtered_search_issues_analytics.js
3. Make sure all of the supported filters (and their negations) are properly formatted and being passed in as variables to the GraphQL query in total_issues_analytics_chart.vue