deps: bump consul/api version for transparent proxy

During refactoring of the CSI jobs, the EBS test dropped stopping the jobs
before checking that the claims were released.

e2e: get consul ent in e2e packer builds

Using Consul Enterprise is going to be necessary for testing Nomad's
Consul Namespace integration in Nomad v1.1 in e2e.

Fix link in error for missing variable

UI: No downloads in test

This followup to #10066 adds a step to clear the one-time token
from the URL after the application has loaded. The delay is
required for it to actually clear, but only when the OTT is present
to avoid slowing down the entire test suite.

command/agent: fix dropped test errors

Consul allows specifying the HTTP body to send in a health check. Nomad
uses Consul for health checking so this just plumbs the value through to
where the Consul API is called.

There is no validation that `body` is not used with an incompatible
check method like GET.

deps: upgrade go-plugin dependency

This PR brings go-plugin up to date from ~v1.0.1 to v1.4.0 (about 18 months)
with a grab-bag of bux fixes.

api: set operator query meta

Set the query meta for LicenseGet request. It's expected by api consumers to determine the raft index.

Also, remove protobuf installation: it's not used anymore.

"Bottles" have been migrated to GitHub packages, so we need to update homebrew
to point to that new source before installing the `protobuf` formula.