Enable no-multi-assignment in JS files

.eslintrc.yml

app/assets/javascripts/lib/utils/common_utils.js

app/assets/javascripts/line_highlighter.js

app/assets/javascripts/monitoring/components/dashboard.vue

app/assets/javascripts/monitoring/components/graph.vue

app/assets/javascripts/network/branch_graph.js

...pts/pages/projects/graphs/show/stat_graph_contributors.js

...ages/projects/graphs/show/stat_graph_contributors_util.js

app/assets/javascripts/profile/gl_crop.js

app/assets/javascripts/project_find_file.js

...sets/javascripts/prometheus_metrics/prometheus_metrics.js

app/assets/javascripts/users_select.js

...ipts/vue_merge_request_widget/components/memory_usage.vue

ee/app/assets/javascripts/mirrors/mirror_pull.js

spec/javascripts/gl_field_errors_spec.js

spec/javascripts/helpers/user_mock_data_helper.js

...cripts/profile/account/components/update_username_spec.js

spec/javascripts/test_bundle.js