Clean up Program.cs

[davidfowl]

Removed unnecessary API calls and added await.

Changes

Please provide a brief description of the changes here.

Merge Requirements

For new features contributions please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[cartersocha]

Please add a change log entry too

[puckpuck]

I'm a big fan of a change that reduces the lines of code and makes it easier to read.

Thanks for the this.

[davidfowl]

Please add a change log entry too

Let me know if there's something else that needs to be done.