ref: convert globalSelection.js to typescript (#55093)

fixtures/js-stubs/globalSelection.js → fixtures/js-stubs/globalSelection.ts

@@ -1,4 +1,6 @@
-export function GlobalSelection(params = {}) {
+import {PageFilters} from 'sentry/types';
+
+export function GlobalSelection(params: Partial<PageFilters> = {}): PageFilters {
   return {
     projects: [1],
     environments: ['production', 'staging'],
@@ -6,7 +8,7 @@ export function GlobalSelection(params = {}) {
       start: '2019-10-09T11:18:59',
       end: '2019-09-09T11:18:59',
       period: '',
-      utc: 'true',
+      utc: true,
     },
     ...params,
   };