Renamed store files to .ts

frontend/src/api.ts

frontend/src/store/actions.ts

frontend/src/store/getters.ts

frontend/src/store/grady_speak.ts

frontend/src/store/modules/authentication.ts

...rc/store/modules/feedback_list/feedback-search-options.ts

frontend/src/store/modules/feedback_list/feedback-table.ts

frontend/src/store/modules/student-page.ts

frontend/src/store/modules/submission-notes.ts

frontend/src/store/modules/subscriptions.ts

frontend/src/store/modules/ui.ts

frontend/src/store/mutations.ts

frontend/src/store/plugins/lastInteractionPlugin.ts

frontend/src/util/helpers.ts