[otelcol] Improve error message when connectors lead to ambiguous IDs

[mx-psi]

When defining a pipeline, a component ID on the receivers or exporters section can be ambiguous if there is both a receiver/exporter and a connector with said ID.

For example, if we were to add a datadog connector, with the following configuration:

Sample ambiguous configuration (click to expand)

receivers:
  datadog:

exporters:
  datadog:
    api::key: ${env:DD_API_KEY}

connectors:
  datadog:

service:
  pipelines:
    traces:
      receivers: [datadog]
      exporters: [datadog]
    metrics:
      receivers: [datadog]
      exporters: [datadog]

will error out with

Error: invalid configuration: connectors::datadog: there's already an exporter named "datadog"

A valid way to work around this is to use different IDs for the receiver/exporter and the connector:

Sample unambiguous configuration (click to expand)

receivers:
  datadog:

exporters:
  datadog:
    api::key: ${env:DD_API_KEY}

connectors:
  datadog/connector:

service:
  pipelines:
    traces:
      receivers: [datadog]
      exporters: [datadog/connector]
    metrics:
      receivers: [datadog/connector]
      exporters: [datadog]

We should improve the error message given in this case to something closer to the following:

Error: invalid configuration: ambiguous ID 'datadog': Found both 'datadog' exporter and 'datadog' connector.
Add a suffix to one of the components' IDs to eliminate ambiguity (e.g. rename 'datadog' connector to 'datadog/connector')

The necessary information is available here.

---

Originally discussed in open-telemetry/opentelemetry-collector-contrib#19740 (comment)