aurweb: send traces to correct route for the otlp endpoint

Partially supersedes !866 (merged) (will do the rest of that in follow-ups).

In AUR, we actually use this line but we somehow don't in our production AUR config.

I tested this locally and the new setting works. I tested it by setting

distributor:
  receivers:
    otlp:
      protocols:
        http:
          endpoint: tempo:4318
  log_received_spans:
    enabled: true

in tempo.yml. This will cause tempo to log any traces it receives. When AUR's config.dev was set to

[tracing]
otlp_endpoint = http://tempo:4318/v1/traces

this would output something as opposed to when it was set to just

[tracing]
otlp_endpoint = http://tempo:4318

• Rolled out to production

requested review from @jelle, @klausenbusk, and @gromit

assigned to @svenstaro

changed the description

approved this merge request

Seems trivial enough, let's deploy and see if it works

mentioned in commit 1aad79d9

merged

marked the checklist item Rolled out to production as completed

added statusdeployed label