chore: added sprintf in logger (#181)

## Summary
Fixed logging message in the logger, added sprintf in utils.

## Test plan
All unit tests and Integration tests pass.

## Ticket 
[OASIS-8220](https://optimizely.atlassian.net/browse/OASIS-8220)

Author: shaharyar123

src/logger.tsx

@@ -15,23 +15,20 @@
  */
 
 import * as optimizely from '@optimizely/optimizely-sdk';
+import { sprintf } from './utils';
 const logHandler = optimizely.logging.createLogger({ prefix: '[React-SDK]' });
 
 export const logger = {
   warn: (msg: string, ...splat: any[]) => {
-    // @ts-ignore
-    return logHandler.log(optimizely.enums.LOG_LEVEL.WARNING, msg, ...splat);
+    return logHandler.log(optimizely.enums.LOG_LEVEL.WARNING, sprintf(msg, ...splat));
   },
   info: (msg: string, ...splat: any[]) => {
-    // @ts-ignore
-    return logHandler.log(optimizely.enums.LOG_LEVEL.INFO, msg, ...splat);
+    return logHandler.log(optimizely.enums.LOG_LEVEL.INFO, sprintf(msg, ...splat));
   },
   debug: (msg: string, ...splat: any[]) => {
-    // @ts-ignore
-    return logHandler.log(optimizely.enums.LOG_LEVEL.DEBUG, msg, ...splat);
+    return logHandler.log(optimizely.enums.LOG_LEVEL.DEBUG, sprintf(msg, ...splat));
   },
   error: (msg: string, ...splat: any[]) => {
-    // @ts-ignore
-    return logHandler.log(optimizely.enums.LOG_LEVEL.ERROR, msg, ...splat);
+    return logHandler.log(optimizely.enums.LOG_LEVEL.ERROR, sprintf(msg, ...splat));
   },
 };

src/utils.tsx

@@ -145,3 +145,17 @@ export function createFailedDecision(flagKey: string, message: string, user: Use
   };
 }
 
+export function sprintf(format: string, ...args: any[]): string {
+  let i = 0;
+  return format.replace(/%s/g, () => {
+    const arg = args[i++];
+    const type = typeof arg;
+    if (type === 'function') {
+      return arg();
+    } else if (type === 'string') {
+      return arg;
+    } else {
+      return String(arg);
+    }
+  });
+}