Fix: Don't sort in pie function

[w33ble]

Closes #27077

Don't sort data by labels in pie function, so that the user's sorting is preserved. Tests were also removed or updated.

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Below, note that the order of the data is preserved in the pie chart, instead of being sorted alphabetically by label name.

[elasticmachine]

Pinging @elastic/kibana-canvas

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[cqliu1]

LGTM 👍 Tested with the flights sample data and it works!

filters
| esdocs index="kibana_sample_data_flights" fields=""
| ply by="Carrier" fn={math "sum(AvgTicketPrice)"}
| sort by="value" reverse=false 
| pointseries color="Carrier" size="value"
| pie
| render

[monfera]

Great PR! If one has a single, static pie chart then we most often need value based sorting. As Canvas is data driven, and can sport multiple piecharts on the same page in a grid formation (with like data), these are legit uses:

• if the data gets updated frequently, eg. every few seconds or minutes, an alternative option is to keep slice indices fixed, so that slice areas / angles tween in place, rather than abruptly relocate (though for some purposes, slices rotating into a new position may be desirable, to make shifts in ranking salient)
• when creating a small multiples chart with a row or grid of pie charts (eg. per country sales), per-pie value ordering is often the best, but some users may prefer consistent pie ordering across elements of the small multiple chart
• if the categories form a natural order, this may trump the value order (eg. colors, magnitudes, basically anything that's a discretization of a continuous measure eg. 0 - 10 years old; 10-20 years old etc.) - in these cases, the category order should prevail

It looks like the change can alter preexisting workbooks, which is fine as it's not yet in GA, and it's clearly the better route. The pie is a renderer and any sorting can be relegated to a previous data processing step, otherwise we'd duplicate and couple data processing in pie.

[w33ble]

It looks like the change can alter preexisting workbooks, which is fine as it's not yet in GA, and it's clearly the better route. The pie is a renderer and any sorting can be relegated to a previous data processing step, otherwise we'd duplicate and couple data processing in pie.

Exactly. And any existing pie charts that are not "incorrect" can be fixed by adding a | sort to the expression.