Reduce opacity of disabled checkbox control indicator

[ggdouglas]

Fixes #6734

Changes proposed in this pull request:

Updates checkbox control indicators (tick and indeterminate dash) on disabled checkbox controls to use a reduced opacity. This aligns with design intent and provides better signal that the checkbox control is disabled.

Reviewers should focus on:

Checkbox and Checkbox card

Screenshot

Before	After

Accessibility / Contrast Check

Light Mode

https://webaim.org/resources/contrastchecker/?fcolor=FFFFFF80&bcolor=99B8E9
WCAG AA: Fail (Graphical Objects and User Interface Components)

Dark Mode

https://webaim.org/resources/contrastchecker/?fcolor=FFFFFF80&bcolor=25497D
WCAG AA: Pass (Graphical Objects and User Interface Components)

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Type

• Feature
• Improvement
• Fix
• Break
• Deprecation
• Manual task
• Migration

Description

Reduce opacity of disabled checkbox control indicator

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[svc-palantir-github]

Reduce opacity of disabled checkbox control indicator

Build artifact links for this commit: documentation | landing | table | demo

This is an automated comment from the deploy-preview CircleCI job.

[invliD]

According to W3C, high contrast is not required for disabled elements, so this change is fine.

User Interface Components that are not available for user interaction (e.g., a disabled control in HTML) are not required to meet contrast requirements.