Make extension error more readable

[sumo-drosiek]

Error: failed to start extensions: collector registration failed: failed to register the collector, got HTTP status code: 401; failed to shutdown pipelines: no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running
Feb 22 08:35:51 ip-10-0-16-79 otelcol-sumo[19174]: 2023/02/22 08:35:51 collector server run finished with error: failed to start extensions: collector registration failed: failed to register the collector, got HTTP status code: 401; failed to shutdown pipelines: no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running; no existing monitoring routine is running

We should remove no existing monitoring routine is running from error message as it makes it unreadable

[sumo-drosiek]

Related upstream issue: open-telemetry/opentelemetry-collector#7078