Fix splunkhec receiver auth registration

[dehaansa]

PR Description

The splunkhec receiver would log the following error when attempting to use authentication as the extensions were not recognized in the internal host interface implementation.

ts=... level=error msg="failed to start scheduled component" component_path=/ component_id=otelcol.receiver.splunkhec.splunk_hec err="failed to resolve authenticator \"bearertokenauth/otelcol_auth_bearer_creds_server\": authenticator not found"

Notes to the Reviewer

A simple config like the following will show the error on main, and no error on this branch.

otelcol.auth.bearer "creds" {
	scheme = "Splunk"
	token  = "test_token"
}

otelcol.receiver.splunkhec "splunk_hec" {
	auth = otelcol.auth.bearer.creds.handler

	output {
		logs    = [otelcol.exporter.debug.default.input]
	}
}

otelcol.exporter.debug "default" {}

PR Checklist

• CHANGELOG.md updated