[Self-Host] fetch engine does not support proxy settings

[mschfh]

Describe the Issue
The fetch scraper does not support proxy settings.

Expected Behavior
The fetch scraper should use the same proxy settings as the playwright-service:

PROXY_SERVER=
PROXY_USERNAME=
PROXY_PASSWORD=

Environment (please complete the following information):

• N/A

Logs

worker-1              | 2025-01-03 16:30:37 info [ScrapeURL:]: Scraping via playwright...
worker-1              | 2025-01-03 16:30:43 info [ScrapeURL:]: An unexpected error happened while scraping with playwright.
worker-1              | 2025-01-03 16:30:43 info [ScrapeURL:]: Scraping via fetch...
worker-1              | 2025-01-03 16:30:43 info [ScrapeURL:]: Scrape via fetch deemed successful.

Configuration
N/A

Additional Context

This should be fixable by adding a ProxyAgent and passing it via the dispatcher parameter here:
https://github.com/mendableai/firecrawl/blob/87757d9b8e6bacc658b48832deb47c51eaf7412a/apps/api/src/scraper/scrapeURL/engines/fetch/index.ts#L17C7-L20

[mr-v-v-v]

Yes, I've been waiting for this feature for a long time. There's also an issue here:
#925