Cycle 2024.7: Unify slope and line charts

[sophiamersmann]

Make slope charts more readable and universally available alongside line charts, by harmonizing their selection/focus states.

Checklist

More details in Notion

Chart type switching

• 🎉 (grapher) support multiple chart types / TAS-694 #4159 (3d)
  • Migrate configs: make type into chartTypes, a list of chart types
• 🎉 (slope) feature parity with line charts / TAS-708 #4192 (3d)
  • Add support for multiple y-indicators
  • Add support for a custom missing data strategy
  • Add support for relative mode
  • Drop support for a categorical colour indicator, and have a fallback for when line charts have a numerical colour indicator
  • Add support for faceting
• 🎉 (slope) add tolerance / TAS-719 #4205 (3d)
• ✨ (slope) redesign #4222 (3d)
• 🎉 make line/slope switching available to authors / TAS-720 #4207 (0.5d)
  • Add a slope chart toggle in the admin (1h)
  • Add supports for switching chart types in explorers (3h)
• Migrate existing slope charts (1d)
  • Find slope charts that have a line chart sibling, add it to the sibling and delete the slope chart
  • Migrate stand-alone slope charts that don't have a line chart sibling
  • Spreadsheet v0
  • Spreadsheet v1
• Manually update GDoc links and unpublish charts

Focus state

• Add focus state to Grapher (5d)
  • Add a new config field, focusedMarks
  • Update scatter plots and Marimekko charts to use focusedMarks instead of selectedEntityNames
  • Add focus state to line and slope charts
  • Allow to choose focused elements in the admin
• Migrate line charts to use focused entities that currently "fake" focus behaviour (0.5d)

Related work

• 🔨 (grapher) replace some enum types / TAS-709 #4170
• Support editing array fields in the bulk chart editor Support filtering by chart type in the bulk chart editor
• Refactor how Grapher decides to hide labels in the controls row to avoid overflow
• Optimise slope charts for Figma
• Refactor 'lineChartThatTurnedIntoDiscreteBar' by showing 'Discrete bar' as tab
• Add support for faceting slope charts