test: felt type to_string tests #492

Job	Run time
Build starknet-ff features	1m 18s
Build C++ integration example	1m 9s
Build starknet-curve features	1m 0s
Build starknet-crypto-codegen features	59s
Build starknet-crypto features	1m 1s
Build starknet-core features	1m 43s
Build starknet-providers features	2m 1s
Build starknet-signers features	1m 9s
Build starknet-accounts features	1m 44s
Build starknet-contract features	1m 22s
Build starknet-macros features	1m 14s
Build starknet features	2m 5s
	16m 45s

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