updated param name from METRIC_NAME to METRIC_NAME1 on thresholds.md

[mustafasahin0]

What?

updated param name from METRIC_NAME to METRIC_NAME1 on thresholds.md to make it in sync with explanations in the documentation.

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Related PR(s)/Issue(s)

[heitortsergent]

@mustafasahin0 thanks for the PR! We just released k6 v0.48, would you mind making the change in this file as well? https://github.com/grafana/k6-docs/blob/main/docs/sources/v0.48.x/using-k6/thresholds.md?plain=1#L99

And thank you for filling out the PR template! 🙇

[mustafasahin0]

Hi @heitortsergent :) Updated v0.48 as well

[heitortsergent]

Thanks @mustafasahin0!