Preselect all projects in group coverage analytics

Instead of waiting for the user to select some projects in the dropdown
Default to "All projects", which selects all projects from the dropdown
(the first page of projects with coverage data from the last 30 days)

Changelog: changed
EE: true

ee/app/assets/javascripts/analytics/repository_analytics/components/select_projects_dropdown.vue

@@ -61,7 +61,7 @@ export default {
       groupProjects: [],
       projectsPageInfo: {},
       projectSearchTerm: '',
-      selectAllProjects: false,
+      selectAllProjects: true,
     };
   },
   computed: {

ee/app/assets/javascripts/analytics/repository_analytics/components/test_coverage_table.vue

@@ -68,7 +68,7 @@ export default {
   },
   data() {
     return {
-      allProjectsSelected: false,
+      allProjectsSelected: true,
       allCoverageData: [], // All data we have ever received whether selected or not
       hasError: false,
       isLoading: false,