Fix periodic failure of DataTransferSessionWrongChecksumMigration unit test

Periodically, we see the following failure in the unit tests:

[ RUN      ] OStoreDBPlusMockSchedulerTestVFS/DataTransferSessionTest.DataTransferSessionWrongChecksumMigration/0
unknown file: Failure
C++ exception with description "No such archive file with ID 4
/builds/cta/CTA/build_rpm/RPM/BUILD/cta-5-13038262gitb44437f1/build/common/libctacommon.so.0(cta::exception::Backtrace::Backtrace(bool)+0x6b) [0x7f102b8a823d]
/builds/cta/CTA/build_rpm/RPM/BUILD/cta-5-13038262gitb44437f1/build/common/libctacommon.so.0(cta::exception::Exception::Exception(std::basic_string_view<char, std::char_traits<char> >, bool)+0x91) [0x7f102b8a94fd]
/builds/cta/CTA/build_rpm/RPM/BUILD/cta-5-13038262gitb44437f1/build/catalogue/libctacatalogue.so.0(cta::catalogue::RdbmsArchiveFileCatalogue::getArchiveFileById(unsigned long) const+0xd6) [0x7f1032ec7416]
/builds/cta/CTA/build_rpm/RPM/BUILD/cta-5-13038262gitb44437f1/build/tapeserver/castor/tape/tapeserver/daemon/libctatapeserverdaemonunittests.so.0(unitTests::DataTransferSessionTest_DataTransferSessionWrongChecksumMigration_Test::TestBody()+0x144a) [0x7f1033e0fcc2]
/lib64/libgtest.so.1.11.0(+0x4fe0c) [0x7f1033be2e0c]
/lib64/libgtest.so.1.11.0(testing::Test::Run()+0xd6) [0x7f1033bc3826]
/lib64/libgtest.so.1.11.0(testing::TestInfo::Run()+0x1a0) [0x7f1033bc39f0]
/lib64/libgtest.so.1.11.0(testing::TestSuite::Run()+0xd9) [0x7f1033bc3af9]
/lib64/libgtest.so.1.11.0(testing::internal::UnitTestImpl::RunAllTests()+0x4e5) [0x7f1033bd2fc5]
/lib64/libgtest.so.1.11.0(testing::UnitTest::Run()+0x1a8) [0x7f1033bd07c8]
tests/cta-unitTests() [0x4064f3]
tests/cta-unitTests() [0x40639f]
/lib64/libc.so.6(+0x295d0) [0x7f1028e875d0]
/lib64/libc.so.6(__libc_start_main+0x80) [0x7f1028e87680]
tests/cta-unitTests() [0x406265]
" thrown in the test body.
[  FAILED  ] OStoreDBPlusMockSchedulerTestVFS/DataTransferSessionTest.DataTransferSessionWrongChecksumMigration/0, where GetParam() = 8-byte object <C0-6B FB-33 10-7F 00-00> (810 ms)