fixes for private spot GET calls, improve signing process, add private read tests for spot & linear

test/linear/private.read.test.ts

@@ -1,9 +1,5 @@
 import { LinearClient } from '../../src/linear-client';
-import {
-  notAuthenticatedError,
-  successResponseList,
-  successResponseObject,
-} from '../response.util';
+import { successResponseList, successResponseObject } from '../response.util';
 
 describe('Public Linear REST API Endpoints', () => {
   const useLivenet = true;
@@ -20,9 +16,6 @@ describe('Public Linear REST API Endpoints', () => {
   });
 
   const symbol = 'BTCUSDT';
-  const interval = '15';
-  const timestampOneHourAgo = new Date().getTime() / 1000 - 1000 * 60 * 60;
-  const from = Number(timestampOneHourAgo.toFixed(0));
 
   describe('Linear only private GET endpoints', () => {
     it('getApiKeyInfo()', async () => {