feat: add accessibility support to loading state components

[adrienzheng-cb]

Accessibility improvements:

• Add role="status", aria-live="polite", and accessibilityLabel to
  Fallback, Spinner, and LottieStatusAnimation on web and mobile
• LottieStatusAnimation auto-generates labels based on status
• Update Fallback docs with accessibility guidance and grouping examples

Test improvements:

• Add shape, width variant, and accessibility tests for Fallback
• Add size variant and accessibility tests for Spinner
• Add cardSuccess and status transition tests for LottieStatusAnimation

Refactoring:

• Move useFallbackShape hook to @coinbase/cds-common for cross-platform use
• Use shapeBorderRadius tokens in RemoteImage/RemoteImageGroup
• deprecated all exports from LottieStatusAnimationProps file in commons
• renamed LottieStatusAnimationType to LottieStatus
• removed redudant usePreviousValue logic from ProgressBar

What changed? Why?

Root cause (required for bugfixes)

UI changes

iOS Old	iOS New
old screenshot	new screenshot

Android Old	Android New
old screenshot	new screenshot

Web Old	Web New
old screenshot	new screenshot

Testing

How has it been tested?

• Unit tests
• Interaction tests
• Pseudo State tests
• Manual - Web
• Manual - Android (Emulator / Device)
• Manual - iOS (Emulator / Device)

Testing instructions

Illustrations/Icons Checklist

Required if this PR changes files under packages/illustrations/** or packages/icons/**

• verified visreg changes with Terran (include link to visreg run/approval)
• all illustration/icons names have been reviewed by Dom and/or Terran

Change management

type=routine
risk=low
impact=sev5

automerge=false

[cb-heimdall]

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[adrienzheng-cb]

The entire usePreviousValue logic is redundant. We just need to initialize the animated progress value based on disableAnimateOnMount and that is it.
We also use the same simple logic in ProgressCircle component. Not sure why ProgrssBar was over-complicated

[hcopp]

We might want to test this part out with @samcartersmith since a customer might have several dozen fallbacks on the page at a time.

[samcartersmith]

@hcopp That's why we went with this label vs an aria-live monstrous amount of noise. I think if there is a page with 20 fallbacks that are all persistent long enough for a user to arrow through them it will give a better understanding of the entire page is struggling to load.

[maximo-macchi-cb]

I'd suggest to avoid mentioning the default label. We want to encourage customers to pass in their own a11y labels for i18n support. Your example below helps to encourage this. The default label is just a fallback (pun not intended) in case a label isn't passed in. It's better than nothing but not the ideal label.

Suggested change

	Fallback includes a visually hidden "Loading" label by default, which screen readers will announce. You can customize this with the `accessibilityLabel` prop. Wrap Fallback in a live region container to announce loading state changes.
	Fallback has an `accessibilityLabel` prop to describe the loading state for assistive technologies. Wrap Fallback in a live region container to announce loading state changes.

[maximo-macchi-cb]

Small nit, can we rephrase this to inform customers about the prop but not require its usage? Using aria-hidden is helpful in some cases but in others may not be ideal.

Suggested change

	For multiple Fallbacks, add `aria-hidden` to all of them and provide your own visually hidden label:
	`aria-hidden` can be passed into a Fallback. This can be useful if you render multiple Fallbacks in an area and would prefer to have a parent container have the aria-label needed for the accessibility API. Whether it's a parent container or each Fallback, there needs to be an element with an `aria-label` indicating a loading state.