utopia-gen: Adjust params code to not set `nullable` on `Option` for … #2885

Job	Run time
typos	6s
test (utoipa)	57s
test (examples)	9m 18s
test (utoipa-gen)	2m 27s
test (utoipa-swagger-ui-vendored)	8s
test (utoipa-swagger-ui)	2m 43s
test (utoipa-redoc)	1m 32s
test (utoipa-rapidoc)	1m 14s
test (utoipa-scalar)	1m 8s
test (utoipa-axum)	40s
test (utoipa-config)	34s
test (utoipa-actix-web)	1m 1s
	21m 48s

Provide feedback