feat: allow chain ID duplications in profiles

There are legitimate use cases for defining networks with the same chain
IDs - devnets, different RPC URLs for accessing the same network, etc..
Starkli should not enforce chain ID uniqueness.

One unfortunate side effect of this is that when using `--rpc` directly,
we can no longer uniquely match the chain ID fetched to a network
defined in the profile (this matching doesn't matter now, but will do in
the future when we have network-specific settings). This is not ideal
but still fine as it's expected that those who define custom networks
are likely to use `--network` instead of `--rpc` anyways. And by using
`--network` directly, users can always uniquely choose the network they
want the settings applied.

src/profile.rs

@@ -1,5 +1,4 @@
 use std::{
-    collections::{hash_map::Entry, HashMap},
     fmt::Display,
     io::{Read, Write},
     path::PathBuf,
@@ -83,23 +82,6 @@ impl Profiles {
             );
         }
 
-        if let Some(default_profile) = loaded_profiles.profiles.get(DEFAULT_PROFILE_NAME) {
-            // Checks chain ID duplication
-            let mut chain_id_last_used_in_network = HashMap::new();
-            for (network_id, network) in default_profile.networks.iter() {
-                match chain_id_last_used_in_network.entry(network.chain_id) {
-                    Entry::Occupied(entry) => anyhow::bail!(
-                        "invalid profile `default`: networks {} and {} have the same chain ID",
-                        entry.get(),
-                        network_id
-                    ),
-                    Entry::Vacant(entry) => {
-                        entry.insert(network_id);
-                    }
-                }
-            }
-        }
-
         Ok(loaded_profiles)
     }