Remove Azure pipeline approval requirement

[thekaveman]

Our Azure DevOps pipeline requires approval for the terraform apply stage.

We added this as part of the refactor towards tag-based deployment. In practice, all engineers are almost always on a call doing the release together, and this approval stage hasn't been necessary or useful.

Let's remove it entirely.

[angela-tran]

I was able to install the Azure Pipelines app into Cal-ITP Slack. I signed in to it using my Azure DevOps account. Entering /azpipelines subscribe [pipeline url] gave me back a message of Configuration failed. Please make sure that the organization '*****' exists and that you have sufficient permissions. (***** is where the org name is)

Found from Azure DevOps docs that:

For Azure DevOps, you need to be in the Project Collection Administrators or Project Administrators group to set up a Slack subscription.

[thekaveman]

We decided that the pipeline approvals aren't necessary, and removing them will represent a quality of life improvement for engineers. Rewrote this ticket to reflect that.

[angela-tran]

Follow-up needed: #480