Two iPad test failures for FIAM with Xcode 13

[paulb777]

From the raw log at https://github.com/firebase/firebase-ios-sdk/runs/3666339632?check_suite_focus=true:

2021-09-21T17:32:58.2960150Z Test Suite InAppMessagingDisplay-UITests.xctest started
2021-09-21T17:32:58.3180100Z InAppMessagingDisplayBannerViewUITests
2021-09-21T17:33:14.4955550Z ✓ testBannerViewWithLargeBody (16.211 seconds)
2021-09-21T17:33:29.0585690Z ✓ testBannerViewWithLongTitle (14.563 seconds)
2021-09-21T17:33:49.5265330Z ✗ testBannerViewWithoutImage, XCTAssertTrue failed
2021-09-21T17:34:03.4313290Z ✓ testBannerViewWithThinImage (13.688 seconds)
2021-09-21T17:34:18.1182830Z ✓ testBannerViewWithWideImage (14.689 seconds)
2021-09-21T17:34:32.8336260Z ✓ testNormalBannerView (14.712 seconds)
2021-09-21T17:34:32.8502160Z InAppMessagingDisplayCardViewUITests
2021-09-21T17:35:42.3828810Z ✗ testHugeImage, Asynchronous wait failed: Exceeded timeout of 60 seconds, with unfulfilled expectations: "Expect predicate exists == 0 for object "message-card-view" Other".

[paulb777]

Once fixed, the iPad tests should be restored at https://github.com/firebase/firebase-ios-sdk/blob/master/.github/workflows/inappmessaging.yml#L39, that was disabled in #8676