Per the documentation (here and here), you need to create an API key in the developer console. We use G-Suite Enterprise and our G-Suite admins have blocked the ability for users to do anything in the developer console.
I have a Sheets bounded GAS project that is deployed as a web-app and set to execute as me. I want to show the Google Picker dialog such that users can upload files and/or select files from THEIR Google Drive.
Is this possible?
Is this possible?
No, this is not possible. An API key must be created and for this developer console access is required.
You need to contact your G Suite admins to allow Developer console access in order to create GCP projects. For security reasons there isn't a way around this and unfortunately there is little that the Stack Overflow community would be able to help you with regarding this.