feat(insights): Add division_if for span metrics

[philipphofmann]

Add division_if for span metrics so we can calculate rates such as slow and frozen rates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.08%. Comparing base (b35aea1) to head (e7b01be).
Report is 2 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #72995       +/-   ##
===========================================
+ Coverage   64.40%   78.08%   +13.68%     
===========================================
  Files        6673     6677        +4     
  Lines      298641   298874      +233     
  Branches    51437    51466       +29     
===========================================
+ Hits       192350   233389    +41039     
+ Misses      99806    59219    -40587     
+ Partials     6485     6266      -219     

Files	Coverage Δ
src/sentry/search/events/datasets/spans_metrics.py	86.48% <100.00%> (+0.29%)	⬆️

... and 1708 files with indirect coverage changes

[narsaynorath]

Just a comment about the test setup, but I think the code looks good

[narsaynorath]

These look like they'd pass but that's just because of how the data is being mocked and where the mock data is set up. There's another example of slow frames tests here where the first arg is actually passed as an object which is consistent for the gauge type, I'd suggest changing these to match that type to make sure it's working the way you want for these metrics, e.g.

        self.store_span_metric(
            {
                "min": 1,
                "max": 1,
                "sum": 1,
                "count": 1,
                "last": 1,
            },
            entity="metrics_gauges",
            metric="mobile.slow_frames",
            timestamp=self.six_min_ago,
            tags={"release": "foo"},
        )

Total frames might be the only one that needs to have different values for min/max/sum/count/last when entered

[getsantry]

This pull request has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you add the label WIP, I will leave it alone unless WIP is removed ... forever!

---

"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[narsaynorath]

Looks good, just left a comment on naming. Thanks for finding that column is actually a special arg that we need to define, we won't be able to change that one but we could do the second column