fix(datastore): fix crash in OutgoingMutationQueue

[ameter]

Description of changes: fix(datastore): fix crash in OutgoingMutationQueue

Check points: (check or cross out if not relevant)

• ~~[ ] Added new tests to cover change, if needed~~
• [x] Build succeeds with all target using Swift Package Manager
• [x] All unit tests pass
• [x] All integration tests pass
• [x] Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• ~~[ ] Documentation update for the change if required~~
• [x] PR title conforms to conventional commit style
• ~~[ ] If breaking change, documentation/changelog update with migration instructions~~

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