feat(ui): migrate Mosaic Heading and Text to StyleX #31509

Job	Run time
Check Permissions	10s
Build Packages	1m 0s
Formatting \| Dedupe \| Changeset	1m 1s
Unit Tests (**)	3m 16s
Unit Tests (**)	3m 28s
Static analysis	2m 9s
Publish with pkg-pr-new	1m 16s
Bundle size	51s
Integration Tests (fastify, chrome)	1m 49s
Integration Tests (ap-flows, chrome)	2m 21s
Integration Tests (vue, chrome)	2m 6s
Integration Tests (nuxt, chrome)	2m 29s
Integration Tests (sessions, chrome)	2m 38s
Integration Tests (sessions:staging, chrome)	2m 39s
Integration Tests (react-router, chrome)	2m 0s
Integration Tests (handshake:staging, chrome)	1m 34s
Integration Tests (express, chrome)	2m 5s
Integration Tests (custom, chrome)	2m 37s
Integration Tests (quickstart, chrome, 16)	2m 26s
Integration Tests (nextjs, chrome, 15)	6m 38s
Integration Tests (machine, chrome)	6m 16s
Integration Tests (localhost, chrome)	1m 56s
Integration Tests (astro, chrome)	3m 23s
Integration Tests (chrome-extension, chrome)	1m 59s
Integration Tests (hono, chrome)	1m 52s
Integration Tests (handshake, chrome)	1m 31s
Integration Tests (generic, chrome)	7m 13s
Integration Tests (quickstart, chrome, 15)	2m 46s
Integration Tests (tanstack-react-start, chrome)	1m 47s
Integration Tests (nextjs, chrome, 16)	6m 28s
Integration Tests (billing, chrome)	5m 10s
Integration Tests (cache-components, chrome, 16)	1m 59s
Integration Tests (electron, chrome)	1m 45s
	1h 28m 38s

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