Misc fixes

- Fix some error messages in transfers
- Fix an error where fetchTransaction was expecting the wrong shape to be returned by /transaction

src/transfers/DepositProvider.ts

@@ -269,7 +269,7 @@ export class DepositProvider extends TransferProvider {
    */
   public getKycUrl(callback_url?: string) {
     if (!this.response || !this.request) {
-      throw new Error(`Run startDeposit before calling fetchKycInBrowser!`);
+      throw new Error(`Run startDeposit before calling getKycUrl!`);
     }
 
     if (

src/transfers/TransferProvider.ts

@@ -185,7 +185,7 @@ export abstract class TransferProvider {
    */
   public async fetchTransaction(
     params: TransactionParams,
-    isWatching: boolean,
+    isWatching: boolean = false,
   ): Promise<Transaction> {
     const {
       asset_code,
@@ -228,7 +228,7 @@ export abstract class TransferProvider {
       },
     );
 
-    const transaction: Transaction = await response.json();
+    const { transaction }: { transaction: Transaction } = await response.json();
 
     return _normalizeTransaction(transaction);
   }

src/transfers/WithdrawProvider.ts

@@ -211,7 +211,7 @@ export class WithdrawProvider extends TransferProvider {
    */
   public async fetchKycInBrowser(windowContext: Window): Promise<KycStatus> {
     if (!this.response || !this.request) {
-      throw new Error(`Run startDeposit before calling fetchKycInBrowser!`);
+      throw new Error(`Run startWithdraw before calling fetchKycInBrowser!`);
     }
 
     if (
@@ -261,7 +261,7 @@ export class WithdrawProvider extends TransferProvider {
    */
   public getKycUrl(callback_url?: string) {
     if (!this.response || !this.request) {
-      throw new Error(`Run startDeposit before calling fetchKycInBrowser!`);
+      throw new Error(`Run startWithdraw before calling getKycUrl!`);
     }
 
     if (