[FEATURE] shadows for osd and toasts

[bmu100]

Submission checklist

• I have searched existing issues and confirmed this has not been requested before.
• I have checked existing pull requests for similar changes.

Feature type

UI / visual improvement

Feature summary

Include toggles for osd and toast shadows.

Motivation / use case

You can disable the borders of osds and toasts. However, disabling them usually results in a lack of contrast (especially when templates are used) due to the absence of shadows.

Proposed solution

I don't know C++ :<. But seeing as how there are shadows for floating panels, it should be possible to implement shadows for these as well.

Alternatives considered

No response

References / related projects

No response

Additional context

No response