Fix Alert banner variant to use Carbon icons

[gilluminate]

Ticket ENG-2891

Description Of Changes

Fix the Alert banner variant to use Carbon icons instead of Ant's built-in icons. The initial Carbon icon integration (PR #7613) missed the banner case because Ant's banner prop implicitly enables icon display and defaults to type="warning" internally, but our HOC was gating icon injection on the explicit showIcon prop and defaulting type to "info".

This mirrors Ant's internal banner defaults in the CustomAlert HOC:

• showIcon resolves to true when banner is set and showIcon isn't explicitly provided
• type resolves to "warning" when banner is set and type isn't explicitly provided

Code Changes

• clients/fidesui/src/hoc/CustomAlert.tsx - Destructure banner prop; compute resolvedType and resolvedShowIcon mirroring Ant's internal defaults; use resolved values for Carbon icon injection and prop passthrough; update JSDoc

Steps to Confirm

1. Run Storybook: cd clients/fidesui && npm run storybook
2. Navigate to Feedback > Alert > Banner story - should show Carbon WarningFilled icon (not Ant's ExclamationCircleFilled)
3. Verify Banner with explicit type="info" shows Carbon InformationFilled
4. Verify Banner with showIcon={false} hides icon entirely
5. Verify non-banner stories (Info, Error, Success, Warning, Compact, Closable) still render correctly

Pre-Merge Checklist

• Issue requirements met
• All CI pipelines succeeded
• CHANGELOG.md updated
  • Updates unreleased work already in Changelog, no new entry necessary
• UX feedback:
  • No UX review needed
• Followup issues:
  • No followup issues
• Database migrations:
  • No migrations
• Documentation:
  • No documentation updates required

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2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
fides-plus-nightly	Ignored	Preview	Mar 12, 2026 5:36pm
fides-privacy-center	Ignored		Mar 12, 2026 5:36pm

[greptile-apps]

Greptile Summary

This PR fixes the CustomAlert HOC so that banner-mode alerts use Carbon icons instead of falling back to Ant Design's built-in ExclamationCircleFilled. The root cause was that the HOC gated icon injection on the explicit showIcon prop and defaulted type to "info", while Ant's banner prop implicitly enables showIcon and defaults type to "warning" internally.

Changes:

• Destructures the banner prop and computes resolvedType (type ?? (banner ? "warning" : "info")) and resolvedShowIcon (showIcon ?? !!banner), mirroring Ant's internal defaults.
• Carbon icon selection and all prop passthrough now use the resolved values, ensuring banner alerts get the WarningFilled Carbon icon by default.
• Explicit showIcon={false} on a banner alert is still correctly respected (since false ?? true evaluates to false via nullish coalescing).
• JSDoc updated to document the banner-mode behavior.

The implementation is clean, well-reasoned, and handles all relevant edge cases correctly.

Confidence Score: 5/5

• This PR is safe to merge — it's a focused, correct bug fix with no side effects on existing non-banner usage.
• The change is minimal (one file, ~15 lines), logically sound, and all edge cases (explicit showIcon={false}, explicit type, custom icon, non-banner alerts) continue to behave correctly due to proper use of nullish coalescing. The fix faithfully mirrors Ant Design's internal banner defaults.
• No files require special attention.

Important Files Changed

Filename	Overview
clients/fidesui/src/hoc/CustomAlert.tsx	Correctly mirrors Ant Design's internal banner defaults by computing resolvedType and resolvedShowIcon before Carbon icon injection; fix is logically sound with no edge-case issues.

_{Last reviewed commit: 6fdb29a}

[speaker-ender]

Approving as is but I'm leaning towards ignoring ant's defaults since they don't have a clear rationale imo.

[speaker-ender]

I'm open to disagreeing with ant's implementation here and choosing our own sane defaults since we are wrapping this.
It seems odd and unintuitive that the default type and showIcon values are different based on the banner prop.

[gilluminate]

I like your thinking! Simplified so all alert types behave consistently - type defaults to "info" and showIcon defaults to false across the board, overriding Ant's banner-specific defaults (type="warning", showIcon=true). No existing banner usages in the codebase, so this is a safe change.