Editing a Chain's chain-id creates a duplicate Chain

[chrishobcroft]

Summary

When editing a Chain's chain-id, then saving, a duplicate Chain is created.

Observed Behaviour

1. Open Walleth
2. Open hamburger menu top left
3. Tap Chain
4. Tap the + to create a new Chain
5. Create a new chain (e.g. use RPC endpoint https://rpc.bordel.wtf/test and name it "Ephemery")

6. Tap the tick to confirm
7. Tap the pencil icon to edit the network named "Ephemery"

8. Increment the chain-id and Network ID by 1

9. Tap the tick to confirm
10. Unexpected behaviour: Observe that there are now 2 (two) networks named "Ephemery"

Expected Behaviour

At step 10, I would expect there to only be 1 (one) network named "Ephemery"

Environment

Version 0.51.4