Add a maxSeries option to the GLQL column chart

What does this MR do and why?

• Adds a maxSeries option to two-dimension GLQL column charts. The largest series keep their own segment and the rest fold into Other (N), the same rule the bar list uses.
• It's opt-in, so column charts that don't set it are unchanged.
• Uses it to cap the DAP Impact "Credits over time" legend at five, which was the open next step for that panel in https://gitlab.com/gitlab-org/gitlab/-/work_items/629739.
• Keeps that panel's second sort key. Segments now follow each flow type's overall total, but the key keeps paging stable when flow types tie on created.
• Adds a TwoDimensionsWithMaxSeries story to the column chart stories.
• Moves the rank-and-fold step into a shared foldSeries helper, used by both the bar list and the column chart.

References

• https://gitlab.com/gitlab-org/gitlab/-/work_items/629739

Screenshots or screen recordings

From the TwoDimensionsWithMaxSeries story: seven languages, with and without maxSeries: 3.

Before	After

How to set up and validate locally

In Storybook:

1. Run yarn storybook:start and open glql/components/presenters/column_chart → Two Dimensions With Max Series.
2. Check the legend shows three languages plus Other (4).

In GDK:

1. Enable the dap_impact_v1 feature flag.
2. Seed DuoWorkflow credits data across more than six flow types.
3. Visit /explore/analytics_dashboards/dap_impact?view=3 and check that "Credits over time" shows five flow types plus Other (N) in its legend.

MR acceptance checklist

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