Merge viz settings correctly

[markbastian]

Currently, Viz settings can come from a bunch of locations (see below). The result of this effort should be a unified path, preferably the metabase.query-processor.middleware.visualization-settings/update-viz-settings middleware, that correctly unifies all of the viz settings in one location.

• Viz settings can come from a bunch of locations:
  - card visualization_settings
  - dashcard visualization_settings
  - defsetting custom-formatting
  - metabase.shared.models.visualization-settings (maybe)
  - defsetting application-colors might also affect static viz rendering (maybe)
• The metabase.query-processor.middleware.visualization-settings/update-viz-settings middleware is a good candidate to resolve these differences
• AC
  • Unit tests similar to Merge metadata correctly #36153 in which pulse cards are rendered on the Clojure side

[markbastian]

This has been completed as part of related work.