refactor: Add details to toImageButtonOptions attribute

[camdecoster]

Description

Update toImageButtonOptions config attribute to provide more details.

Closes #8057.

Changes

• Update attribute info
• Move toImage attribute info to separate file
• Update types per above changes
• Update schema
• Add test

Testing

Check the results of CI.

Notes

• This change tightens the schema and types but shouldn't affect downstream consumers of the schema (like plotly.py)
• The type changes result in more accurate types, but might cause errors for users that have assumed the previous incorrect type structures