refactor: VVMマニフェストで`#[serde(flatten)]`を活用 #3212

Job	Run time
actionlint	16s
rust-lint	4m 12s
shellcheck	11s
validate-cargo-lock	21s
build-and-test-java-api (windows-latest)	6m 45s
build-and-test-python-api (windows-latest)	7m 6s
build-and-test-java-api (macos-latest)	2m 38s
build-and-test-python-api (macos-latest)	3m 14s
build-and-test-java-api (ubuntu-latest)	2m 43s
build-and-test-python-api (ubuntu-latest)	2m 57s
build-unix-cpp-example (macos-latest, osx-x64-cpu-cpp-shared)	1m 53s
build-windows-cpp-example	4m 46s
build-unix-cpp-example (ubuntu-latest, linux-x64-cpu-cpp-shared)	1m 36s
c-header	43s
rust-integration-test-strategy-matrix	1s
rust-unit-test	4m 31s
rust-integration-test (macos-13)	2m 53s
rust-integration-test (ubuntu-20.04)	1m 26s
	48m 12s

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