proxy gen - fix for non-configured proxy and ManagedOption type #413

Job	Run time
Contracts (nightly) / Clippy linter check	1m 11s
Contracts (nightly) / Rust tests	2m 51s
Contracts (nightly) / Test Coverage	7m 6s
Contracts (nightly) / Wasm tests	10m 25s
	21m 33s

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