fix(sdk-coin-flrp): custody wallets no longer require a password

FLRP (Flare P-Chain) is a TSS-only coin — its statics define CoinFeature.TSS
and CoinFeature.MPCV2 but not CoinFeature.MULTISIG. Custody wallets for FLRP
must therefore be created with multisigType='tss', and signing is handled
server-side with no user key material on the client.

Previously, getDefaultMultisigType() returned 'onchain'. This caused
generateWallet({ type: 'custodial' }) to take the onchain-custodial code path
in wallets.ts (line 548), which creates a wallet object whose multisigType the
platform rejects ("Source FLR P wallet is not MPC (multisigType: onchain)").
Any caller that did pass multisigType:'tss' explicitly would correctly use
generateCustodialMpcWallet (no passphrase), but without a matching default the
omission silently produced a broken wallet.

Fix: return multisigTypes.tss from getDefaultMultisigType(), matching the
behaviour of sdk-coin-flr (FLR C-Chain), which correctly defaults to TSS and
has working custody wallets. With this default, generateWallet({ type:
'custodial' }) for FLRP now routes through generateCustodialMpcWallet, which
creates the wallet server-side and requires no passphrase.

Ticket: CECHO-1451
Session-Id: 7a278a4a-2a01-4004-b7bf-1ec86294141e
Task-Id: f3d71be2-ccd9-4342-a175-d342d5857ebe

Author: ArunBala-Bitgo

modules/bitgo/test/v2/unit/wallets.ts

@@ -810,6 +810,44 @@ describe('V2 Wallets:', function () {
       walletNock.isDone().should.be.true();
     });
 
+    it('should create a new FLRP TSS custodial wallet without requiring a passphrase', async function () {
+      const keys = ['1', '2', '3'];
+      const tflrp = bitgo.coin('tflrp');
+
+      const walletParams: GenerateWalletOptions = {
+        label: 'flrp custodial wallet',
+        enterprise: 'enterprise',
+        type: 'custodial',
+        // No multisigType specified — should default to 'tss' for FLRP
+        // No passphrase — custodial wallets must not require one
+      };
+
+      // FLRP is ECDSA, so generateCustodialMpcWallet fetches TSS settings
+      nock('https://bitgo.fakeurl')
+        .get('/api/v2/tss/settings')
+        .reply(200, { coinSettings: { flrp: { walletCreationSettings: {} } } });
+
+      const walletNock = nock('https://bitgo.fakeurl')
+        .post('/api/v2/tflrp/wallet/add')
+        .times(1)
+        .reply(200, { ...walletParams, multisigType: 'tss', keys });
+
+      const flrpWallets = new Wallets(bitgo, tflrp);
+
+      const res = await flrpWallets.generateWallet(walletParams);
+      if (!isWalletWithKeychains(res)) {
+        throw new Error('wallet missing required keychains');
+      }
+      res.wallet.label().should.equal(walletParams.label);
+      should.equal(res.wallet.type(), walletParams.type);
+      res.wallet.multisigType().should.equal('tss');
+      res.userKeychain.id.should.equal(keys[0]);
+      res.backupKeychain.id.should.equal(keys[1]);
+      res.bitgoKeychain.id.should.equal(keys[2]);
+
+      walletNock.isDone().should.be.true();
+    });
+
     it('should create a new TSS SMC wallet', async function () {
       const commonKeychain = 'longstring';
       const seed = 'seed';

modules/sdk-coin-flrp/src/flrp.ts

@@ -68,7 +68,7 @@ export class Flrp extends BaseCoin {
 
   /** inherited doc */
   getDefaultMultisigType(): MultisigType {
-    return multisigTypes.onchain;
+    return multisigTypes.tss;
   }
 
   /** @inheritdoc */

modules/sdk-coin-flrp/test/unit/flrp.ts

@@ -64,7 +64,7 @@ describe('Flrp test cases', function () {
   });
 
   it('should return default multisig type', function () {
-    basecoin.getDefaultMultisigType().should.equal('onchain');
+    basecoin.getDefaultMultisigType().should.equal('tss');
   });
 
   it('should support TSS', function () {