Change pprof labels to be prometheus compatible

[TheFox0x7]

Enables scrapping pprof endpoint for continuous profiling

Closes: #32854

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There's probably room for improvement - for example dropping graceful_lifecycle completely and making with-hammer into with: hammer key value (or something similar). But I'd wait with that for a proper spec in OTel so there there won't be a need to align to spec n times.

Name is compliant with both prometheus regex and OTel recommendation (but not to their semantic conventions):

For each multi-word dot-delimited component of the attribute name separate the words by underscores (i.e. use snake_case).

[lunny]

Is this a breaking change for those upgraded Gitea instance?

[TheFox0x7]

It was marked as such in the fork. However the for it to be breaking someone would actively have to scrape the endpoint for (semi-)automated analysis, which I very much doubt anyone is doing (evidence being that no one complained about it).

If you consider that a real possibility then yes, it is breaking.

[lunny]

The pprof labels was introduced in #19202 and I found there is a grafana mixin introduced in #17758. Maybe this can also be added to grafana mixin in the same PR?

[wxiaoguang]

Maybe this can also be added to grafana mixin in the same PR?

No, there are different, do not mix them at the moment.

[delvh]

Let's measure if it is breaking by whether someone complains 😄

[wxiaoguang]

Let's measure if it is breaking by whether someone complains 😄

Actually it breaks nothing .....