fix(ui): Ensure cssLayerName from appearance is preserved during updateProps #27818

Job	Run time
Check Permissions	6s
Build Packages	1m 16s
Formatting \| Dedupe \| Changeset	57s
Unit Tests (**)	3m 24s
Static analysis	3m 55s
Publish with pkg-pr-new	1m 51s
Unit Tests (**)	2m 16s
Integration Tests (express, chrome)	2m 14s
Integration Tests (localhost, chrome)	2m 40s
Integration Tests (fastify, chrome)	1m 57s
Integration Tests (generic, chrome)	5m 59s
Integration Tests (ap-flows, chrome)	2m 21s
Integration Tests (sessions, chrome)	2m 48s
Integration Tests (react-router, chrome)	2m 23s
Integration Tests (handshake:staging, chrome)	1m 58s
Integration Tests (cache-components, chrome, 16)	2m 49s
Integration Tests (billing, chrome)	4m 53s
Integration Tests (quickstart, chrome, 16)	3m 1s
Integration Tests (vue, chrome)	2m 13s
Integration Tests (sessions:staging, chrome)	3m 0s
Integration Tests (nuxt, chrome)	2m 51s
Integration Tests (nextjs, chrome, 15)	6m 18s
Integration Tests (hono, chrome)	2m 11s
Integration Tests (machine, chrome)	5m 46s
Integration Tests (tanstack-react-start, chrome)	2m 4s
Integration Tests (handshake, chrome)	1m 50s
Integration Tests (chrome-extension, chrome)	2m 33s
Integration Tests (quickstart, chrome, 15)	3m 7s
Integration Tests (astro, chrome)	3m 21s
Integration Tests (nextjs, chrome, 16)	6m 39s
Integration Tests (custom, chrome)	2m 17s
	1h 30m 58s

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