Fix CI: only run unit + mock E2E tests in release workflow #7

Job	Run time
publish	19s
build (ubuntu-latest, bun-linux-x64, mails-linux-x64)	10s
build (macos-latest, bun-darwin-x64, mails-darwin-x64)	12s
build (ubuntu-24.04-arm, bun-linux-arm64, mails-linux-arm64)	11s
build (macos-latest, bun-darwin-arm64, mails-darwin-arm64)	11s
release	13s
	1m 16s

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