scrape: Remove implicit fallback to the Prometheus text format
Remove implicit fallback to the Prometheus text format in case of invalid/missing Content-Type and fail the scrape instead. Add ability to specify a `fallback_scrape_protocol` in the scrape config.
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Signed-off-by: alexgreenbank <alex.greenbank@grafana.com>
Signed-off-by: Alex Greenbank <alex.greenbank@grafana.com>
Co-authored-by: Björn Rabenstein <beorn@grafana.com>
