Is your feature request related to a problem? Please describe.
When working with proportional symbol charts (e.g. bubble scatter plots), I have ran into the issue of needing a size symbol legend.

Describe the solution you'd like
Have the option of a side-by-side and/or nested circle size legend.

Describe alternatives you've considered
I've created a Svelte Playground with a working solution. It utilzes the overlay snippet to draw a nested circle size symbol. The array for the three circles can be user-defined for auto-generated. It works but is a bit verbose.

https://svelte.dev/playground/6ee67430e41f4123bea036d8c9ab89ef?version=5.46.1

Additional context
Screenshot of current solution: