add `polymorphic_serialization` for models and dataclasses #6403

Job	Run time
coverage	1m 10s
test on macos	3m 26s
test-pydantic-integration	1m 17s
build-wasm-emscripten	3m 31s
test 3.9	3m 39s
test on ubuntu	3m 29s
test on windows	6m 15s
test 3.12	3m 33s
test 3.10	3m 42s
test 3.11	3m 37s
build on ${{ matrix.os }} (${{ matrix.target }} - ${{ matrix.interpreter \|\| 'all' }}${{ matrix.os == 'linux' && format(' - {0}', matrix.manylinux == 'auto' && 'manylinux' \|\| matrix.manylinux) \|\| '' }})	0s
build sdist	29s
test 3.14	3m 25s
test graalpy-3.12	5m 26s
test 3.13	3m 22s
lint	47s
test pypy3.10	5m 46s
test 3.14t	3m 36s
test graalpy-3.11	6m 56s
test MSRV	2m 6s
test-debug pypy3.10	3m 20s
rust benchmarks	3m 50s
test-debug 3.13	55s
test pypy3.11	6m 0s
test build on ${{ matrix.target }}-${{ matrix.distro }}	0s
test build on ${{ matrix.platform.os }}	0s
build pgo-optimized on ${{ matrix.platform.os }} / ${{ matrix.interpreter }}	0s
inspect-pypi-assets	0s
check	5s
release	0s
	1h 19m 42s

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