chore: move Milkyway from native to non-native support

Remove milkyway from nativeMainnetChainIdentifiers to transition
it to non-native (KCR) support.

Ref: KEPLR-1767

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: kws1207

src/constants.ts

@@ -41,7 +41,6 @@ export const nativeMainnetChainIdentifiers: string[] = [
   "nillion",
   "bbn",
   "interwoven",
-  "milkyway",
   "atomone",
   "pocket",
   "xrplevm_1440000",