refactor: remove redundant _non_mut suffix from method names

[kilavvy]

This PR removes the redundant _non_mut suffix from two public methods in CheatsConfig to improve API consistency and readability.

• Renamed get_chain_data_by_alias_non_mut → get_chain_data_by_alias
• Renamed get_rpc_url_non_mut → get_rpc_url
• Updated internal method call to use the new name

The _non_mut suffix was redundant since:

• Methods already use &self (non-mutating by design)
• Other methods in the same struct follow the pattern without such suffixes (rpc_endpoint, rpc_urls, set_chain_data)

[onbjerg]

These functions are basically unused, removed in #12245