Changing duplicate {yourApiIdentifier} value when downloaded as sample app

[mchang16-auth]

Background

Currently, this line in api-server.js is:

 ['{yourApiIdentifier}', '{API_IDENTIFIER}'].includes(
    authConfig.authorizationParams.audience
  )

But when the Angular sample app is downloaded from the Quickstarts (both Dashboard and from auth0.com/docs) and the user does not have an API created, this line in api-server.js becomes:

['{yourApiIdentifier}', '{yourApiIdentifier}'].includes(
    authConfig.authorizationParams.audience

This is because '{API_IDENTIFIER}' is being replaced with '{yourApiIdentifier}' when downloaded as a sample app.
Note: this was happening even prior to the changes made in #524, so that PR did not create this text replacing.

Changes

In this PR, we changed ['{yourApiIdentifier}', '{API_IDENTIFIER}'] to authConfig.authorizationParams.audience === '{API_IDENTIFIER}' to remove this duplicated string from happening. This way, it still satisfies both use cases:

• '{API_IDENTIFIER}' is used when a user downloads the sample app straight from Github
• '{yourApiIdentifier}' is used when a user downloads the sample app from a Quickstart