[test] TestSupervisor_setupOwnMetrics is broken on Windows CI

[pjanotti]

Component(s)

cmd/opampsupervisor

Describe the issue you're reporting

https://github.com/open-telemetry/opentelemetry-collector-contrib/actions/runs/11351508374/job/31572243634#step:8:96

The test is not taking into account that the file on Windows uses \r\n on each line end instead of \n like the other systems.

=== FAIL: supervisor TestSupervisor_setupOwnMetrics/DestinationEndpoint_set_-_enable_own_metrics (0.01s)
    supervisor_test.go:1161: 
        	Error Trace:	D:/a/opentelemetry-collector-contrib/opentelemetry-collector-contrib/cmd/opampsupervisor/supervisor/supervisor_test.go:1161
        	Error:      	Not equal: 
        	            	expected: "receivers:\n  # Collect own metrics\n  prometheus/own_metrics:\n    config:\n      scrape_configs:\n        - job_name: 'otel-collector'\n          scrape_interval: 10s\n          static_configs:\n            - targets: ['0.0.0.0:55555']  \nexporters:\n  otlphttp/own_metrics:\n    metrics_endpoint: \"localhost\"\n\nservice:\n  telemetry:\n    metrics:\n      address: \":55555\"\n  pipelines:\n    metrics/own_metrics:\n      receivers: [prometheus/own_metrics]\n      exporters: [otlphttp/own_metrics]\n"
        	            	actual  : "receivers:\r\n  # Collect own metrics\r\n  prometheus/own_metrics:\r\n    config:\r\n      scrape_configs:\r\n        - job_name: 'otel-collector'\r\n          scrape_interval: 10s\r\n          static_configs:\r\n            - targets: ['0.0.0.0:55555']  \r\nexporters:\r\n  otlphttp/own_metrics:\r\n    metrics_endpoint: \"localhost\"\r\n\r\nservice:\r\n  telemetry:\r\n    metrics:\r\n      address: \":55555\"\r\n  pipelines:\r\n    metrics/own_metrics:\r\n      receivers: [prometheus/own_metrics]\r\n      exporters: [otlphttp/own_metrics]\r\n"
make[2]: *** [../../Makefile.Common:131: test] Error 1

[github-actions]

Pinging code owners:

• cmd/opampsupervisor: @evan-bradley @atoulme @tigrannajaryan @BinaryFissionGames

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[evan-bradley]

Thanks for catching this, I'll take care of it.