Rename bannedChars and bannedDigits in string module

Rename bannedChars and bannedDigits in string module: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). Rename bannedChars and bannedDigits in string module Extracted out of https://github.com/faker-js/faker/pull/1155 discussion r922645362 The parameter names bannedChars and…