[Self-Host] call to playwright is failing
## Context
[Self-Host] Calls to the playwright microservice fail when scraping: 'ScrapeURL: An unexpected error happened while scraping with playwright', with the playwright-service logging a JSON parse SyntaxError.
## Verified resolution
Maintainer mogery: the way the worker sent requests to the playwright microservice was wrong; fixed by PR #977 - rebuild the firecrawl image (no need to rebuild playwright-service). Lesson for self-hosters: playwright scraping failures after an upgrade often just need the worker image rebuilt to match the expected microservice protocol.