fix: reset cached style state in Fabric prepareForRecycle to stop stale-markdown flicker

[mvanhorn]

What/Why?

On the Fabric (new architecture) iOS path, recycled EnrichedMarkdown / EnrichedMarkdownText views kept cached style and md4c-flag state from their previous mount, so a recycled view briefly showed stale markdown (a flicker) before the next props update repainted it. prepareForRecycle now resets the cached style state back to the generated-props baseline, and resets _md4cFlags from that same baseline (not the library default), so a recycled view with md4cFlags.latexMath disabled no longer parses $...$ as math. Fixes #110.

Testing

Change is confined to the iOS prepareForRecycle reset path on the Fabric renderer. Verified by code inspection that the reset now mirrors the reset _props baseline so the subsequent updateProps diff applies the incoming flags correctly. On-device iOS/Android runs and the example app were not exercised in this environment, so the iOS/Android build-and-run checklist items are left unchecked for a maintainer with a simulator to confirm.

PR Checklist

• Code compiles and runs on iOS
• Code compiles and runs on Android
• Updated documentation/README if applicable (none needed for this fix)
• Ran example app to verify changes: not performed in this environment (no iOS simulator); reset path verified by inspection and review
• E2E tests are passing
• Required E2E tests have been added (if applicable)