Fix serializing complex values in enums #5305

Job	Run time
test on ubuntu	1m 52s
test on macos	1m 22s
rust benchmarks	2m 27s
test on windows	5m 35s
coverage	2m 5s
lint	1m 3s
test-debug 3.13	1m 4s
test MSRV	2m 16s
test-debug pypy3.10	1m 25s
test-pydantic-integration	1m 57s
test 3.8	1m 51s
build on ${{ matrix.os }} (${{ matrix.target }} - ${{ matrix.interpreter \|\| 'all' }}${{ (((matrix.os == 'linux') && format(' - {0}', (((matrix.manylinux == 'auto') && 'manylinux') \|\| matrix.manylinux))) \|\| '') }})	0s
test 3.9	1m 59s
build sdist	20s
build-wasm-emscripten	2m 27s
test 3.10	1m 55s
test 3.11	1m 55s
test 3.12	2m 1s
build pgo-optimized on ${{ matrix.os }} / ${{ matrix.interpreter }}	0s
test 3.13	1m 56s
test pypy3.9	2m 8s
test pypy3.10	2m 10s
test build on ${{ matrix.target }}-${{ matrix.distro }}	0s
test build on ${{ matrix.os }}	0s
inspect-pypi-assets	0s
check	3s
release	0s
	39m 51s

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