UICollectionView Crash when using delegate publishers and UICollectionViewDiffableDataSource

[TheCoordinator]

Describe the bug The UICollectionView crashes internally when using the delegate publishers such as didSelectItemPublisher and using UICollectionViewDiffableDataSource as dataSource.

To Reproduce

1. Setup a collectionView with UICollectionViewDiffableDataSource as dataSource.
2. Add an example publisher such as didSelectItemPublisher
3. Update dataSource snapshot
4. See crash log

Expected behavior Shouldn't crash

Device:

• OS: [e.g. iOS 14.5]
• CombineCocoa 0.3.0

Additional context

Crash Log:

2021-08-04 11:21:52.800547+0100 App[6134:8095978] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
	0   CoreFoundation                      0x0000000113473fba __exceptionPreprocess + 242
	1   libobjc.A.dylib                     0x0000000112bc1ff5 objc_exception_throw + 48
	2   CoreFoundation                      0x00000001134f2523 _CFThrowFormattedException + 194
	3   CoreFoundation                      0x00000001134f0457 -[__NSArrayM insertObject:atIndex:].cold.2 + 0
	4   CoreFoundation                      0x000000011337114a -[__NSArrayM insertObject:atIndex:] + 1130
	5   Runtime                             0x000000010f64a5b8 unpackInvocation + 1410
	6   Runtime                             0x000000010f649fdd -[ObjcDelegateProxy forwardInvocation:] + 45
	7   CoreFoundation                      0x0000000113478259 ___forwarding___ + 825
	8   CoreFoundation                      0x000000011347a7a8 _CF_forwarding_prep_0 + 120
	9   UIKitCore                           0x000000012ddf07cd -[UICollectionView _notifyDidEndDisplayingCellIfNeeded:forIndexPath:] + 194
	10  UIKitCore                           0x000000012de07b5a -[UICollectionView _reuseCell:notifyDidEndDisplaying:] + 1471
	11  UIKit                               0x0000000150773878 -[UICollectionViewAccessibility _reuseCell:notifyDidEndDisplaying:] + 77
	12  UIKitCore                           0x000000012de17202 -[UICollectionView _updateAnimationDidStop:finished:context:] + 1838
	13  UIKitCore                           0x000000012de169e4 __102-[UICollectionView _updateWithItems:tentativelyForReordering:propertyAnimator:collectionViewAnimator:]_block_invoke.2110 + 77
	14  libdispatch.dylib                   0x0000000119698578 _dispatch_call_block_and_release + 12
	15  libdispatch.dylib                   0x000000011969974e _dispatch_client_callout + 8
	16  libdispatch.dylib                   0x00000001196a7b3f _dispatch_main_queue_callback_4CF + 1152
	17  CoreFoundation                      0x00000001133e18f8 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9
	18  CoreFoundation                      0x00000001133dc169 __CFRunLoopRun + 2781
	19  CoreFoundation                      0x00000001133db1a7 CFRunLoopRunSpecific + 567
	20  GraphicsServices                    0x0000000122ed0d85 GSEventRunModal + 139
	21  UIKitCore                           0x000000012e7184df -[UIApplication _run] + 912
	22  UIKitCore                           0x000000012e71d39c UIApplicationMain + 101
	23  libswiftUIKit.dylib                 0x0000000118266f42 $s5UIKit17UIApplicationMainys5Int32VAD_SpySpys4Int8VGGSgSSSgAJtF + 98
	24  App                                0x000000010ef3c40a $sSo21UIApplicationDelegateP5UIKitE4mainyyFZ + 122
	25  App                                0x000000010ef3c37c $s4App11AppDelegateC5$mainyyFZ + 28
	26  App                                0x000000010ef3c4f9 main + 41
	27  libdyld.dylib                       0x0000000119727bbd start + 1
)
libc++abi: terminating with uncaught exception of type NSException
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
terminating with uncaught exception of type NSException