Update index.ts

exporting type to surpress the TS error: 'Re-exporting a type when 'isolatedModules' is enabled requires using 'export type'.'

Author: Seifeldin-Sabry

src/authentication/azureTokenCredentials/index.ts

@@ -4,5 +4,5 @@
  * See License in the project root for license information.
  * -------------------------------------------------------------------------------------------
  */
-export { TokenCredentialAuthenticationProviderOptions } from "./ITokenCredentialAuthenticationProviderOptions";
+export type { TokenCredentialAuthenticationProviderOptions } from "./ITokenCredentialAuthenticationProviderOptions";
 export { TokenCredentialAuthenticationProvider } from "./TokenCredentialAuthenticationProvider";