Move dependencies/show to dependencies/index

* Remove the extra ".json" from the download endpoint

ee/app/assets/javascripts/dependencies/store/modules/list/getters.js

@@ -9,4 +9,5 @@ export const isJobFailed = state =>
   [REPORT_STATUS.jobFailed, REPORT_STATUS.noDependencies].includes(state.reportInfo.status);
 export const isIncomplete = state => state.reportInfo.status === REPORT_STATUS.incomplete;
 
-export const downloadEndpoint = ({ endpoint }) => `${endpoint}.json`;
+export const downloadEndpoint = ({ endpoint }) =>
+  endpoint.endsWith('.json') ? endpoint : `${endpoint}.json`;

ee/app/views/layouts/nav/sidebar/_project_security_link.html.haml

@@ -24,7 +24,7 @@
           %span= _('Security Dashboard')
 
     - if project_nav_tab?(:dependencies)
-      = nav_link(path: 'projects/dependencies#show') do
+      = nav_link(path: 'projects/dependencies#index') do
         = link_to project_dependencies_path(@project), title: _('Dependency List'), data: { qa_selector: 'dependency_list_link' } do
           %span= _('Dependency List')