Fix activeMailbox is marked as required

flag=none

test plan:
  - Specs pass

qa risk: low

Change-Id: I937b3de616175245f3f4940e5f4ab75ce64adb87
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/277493
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Rob Orton <rob@instructure.com>
QA-Review: Rob Orton <rob@instructure.com>
Product-Review: Rob Orton <rob@instructure.com>

jest/jest-setup.js

@@ -76,7 +76,7 @@ const ignoredErrors = [
   /Render methods should be a pure function of props and state/,
   /The 'screenReaderOnly' prop must be used in conjunction with 'liveRegion'/,
   /The above error occurred in the <.*> component/,
-  /The prop `activeMailbox` is marked as required in `MailboxSelectionDropdown`/,
+  /The prop `avatarName` is marked as required in `UserLink`/,
   /The prop `children` is marked as required in `TruncateText`/,
   /The prop `courseId` is marked as required in `(LatestAnnouncementLink|PublishButton)`/,
   /The prop `currentUserRoles` is marked as required in `ObserverOptions`/,

ui/features/inbox/react/containers/__tests__/MessageListActionContainer.test.js

@@ -54,6 +54,7 @@ describe('MessageListActionContainer', () => {
       <ApolloProvider client={mswClient}>
         <AlertManagerContext.Provider value={{setOnFailure: jest.fn(), setOnSuccess: jest.fn()}}>
           <MessageListActionContainer
+            activeMailbox="inbox"
             onCompose={jest.fn()}
             onReply={jest.fn()}
             onReplyAll={jest.fn()}