fix(ui-motion): stop leaking elementRef onto emotion-wrapped DOM children

[balzss]

Summary

Any <Transition> child written with a css prop logs:

Warning: React does not recognize the `elementRef` prop on a DOM element.
    at span
    at BaseTransition
    at Transition -> DrawerTray -> DrawerLayout

BaseTransition treated typeof child.type === 'object' as "withStyle-decorated InstUI component". That's true of every forwardRef wrapper, including the one emotion's jsx runtime wraps around any element carrying a css prop — and emotion forwards unknown props straight to the DOM node. Introduced in aaa4a58 (#2618), shipped in v11.7.4.

Affects Tray, DrawerTray, RatingIcon v2 and Modal (constrain="parent") — each renders a css child that resolves to a host element.

Changes

• Narrow the check to children that actually declare elementRef in allowedProps. Emotion's wrapper doesn't, so <div css={...}> takes the plain ref path; a withStyle child keeps the chained elementRef.

This is deliberately not a revert. #2618 fixed LX-4014, where a withStyle child plus a running transition made React read ref off the element and warn. I tried the straight revert of renderChildren first — it brings LX-4014 back, confirmed rather than assumed.

Test Plan

Two tests bracket the fix, so neither behaviour can regress into the other:

	old typeof check	plain revert	this PR
elementRef leak on a css host child	❌	✅	✅
LX-4014 ref is not a prop on a withStyle child	✅	❌	✅

• Both failure modes verified by temporarily swapping the implementation, not by reasoning.
• The LX-4014 test uses a real withStyle-decorated child and an actually-running transition — both conditions are required to reproduce, per fix(ui-motion,ui-alerts): capture child DOM via elementRef in Transition to avoid React 'ref is not a prop' warning #2618.
• ui-motion 21 passed. ui-tray ui-drawer-layout ui-modal ui-rating ui-overlays ui-toggle-details ui-tabs ui-popover 229 passed. Browser project (incl. ui-alerts) 190 passed. build:types clean.
• Docs app with devtools open: Alert dismiss/re-add and all three DrawerLayout trays — clean console, no elementref attributes in the DOM.

Fixes INSTUI-5139

Reported by @drakeaharper in #instui — canvas-rce escalates console.error to a failure, so this alone failed 380 tests across 23 files. Supersedes #2667, which proposed the same allowedProps gate.

🤖 Generated with Claude Code

[github-actions]

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[github-actions]

Visual regression report

⚠️ Changes detected.

Status	Count
Unchanged	0
Changed	1
New	96
Removed	32

📊 View full report

Diff images (33)

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_{Baselines come from the visual-baselines branch. They refresh on every merge to master.}