chore: remove 'nillion' from chain identifiers

Eliminate 'nillion' from both nativeMainnetChainIdentifiers and nativeTestnetChainIdentifiers to streamline the list of supported chains.

Author: piatoss3612

src/constants.ts

@@ -38,7 +38,6 @@ export const nativeMainnetChainIdentifiers: string[] = [
   "pirin",
   "xion-mainnet",
   "jackal",
-  "nillion",
   "bbn",
   "interwoven",
   "atomone",
@@ -82,7 +81,6 @@ export const nativeTestnetChainIdentifiers: string[] = [
   "govgen",
   "seda-1-testnet",
   "initiation",
-  "nillion-chain-testnet",
   "athens_7001",
   "mantra-dukong",
   "grand",