Remove the redundant sentence so users will reference from the tutorial link (#187)

remove extra sentence so users will figure out from the tutorial link

Author: avr757

README.md

@@ -57,7 +57,7 @@ This repository is made up of two separate Unity projects. If you would like to
 
 6. Launch Unity and open the `SampleViewer` level (it should open by default).
 
-7. In the hierarchy select the `SampleSwitcher` Game Object and then in the inspector set your [API key](https://developers.arcgis.com/documentation/security-and-authentication/api-key-authentication/). For the detailed steps to create an API key, see [Create and manage an API key tutorials](https://developers.arcgis.com/documentation/security-and-authentication/api-key-authentication/tutorials/create-an-api-key/) in the _Security and authentication guide_. If you don't have the API keys page in your dashboard, upgrade your account to an [ArcGIS Location Platform account](https://location.arcgis.com/sign-up/).
+7. In the hierarchy select the `SampleSwitcher` Game Object and then in the inspector set your [API key](https://developers.arcgis.com/documentation/security-and-authentication/api-key-authentication/). For the detailed steps to create an API key, see [Create and manage an API key tutorials](https://developers.arcgis.com/documentation/security-and-authentication/api-key-authentication/tutorials/create-an-api-key/) in the _Security and authentication guide_.
 
 8. (Optional) If you want to be able to open the `.cs` files in this project and have IntelliSense recognize variable correctly, in Unity navigate to `Edit -> Preferences -> External Tools -> Generate .csproj files for 'local tarball`