Update censorshipConfiguration for China

[UjuiUjuMandan]

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• I have read how to contribute to this project
• I have signed the Contributor License Agreement

Contributor checklist

• I am following the Code Style Guidelines
• I have tested my contribution on these devices:

• Google Pixel 7, Android 14

• My contribution is fully baked and ready to be merged as is
• I ensure that all the open issues my contribution fixes are mentioned in the commit message of my first commit using the Fixes #1234 syntax

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Description

As for China, currently only one front domain works: github.githubassets.com. Most of Google's IPs are blocked, and another 2 domain are blocked by DPI. Therefore, the circumvention works, but is very slow, because Signal has to wait for all others to time out before connecting to github.githubassets.com.

This patch:

1. Updated fUrls to use less UGC websites, which is more likely to be blocked, and use more innocent websites.
2. Set domain fronting configuration for China to Fastly.

• fastly.jsdelivr.net is used by many programers on their blog, I belive the collateral damage is high.
• www.python.org is also programer-related.
• www.gov.uk, lol.

My ISP is China Unicom (AS4837), I've built it and tested on my Google Pixel 7 with Android 14. The circumvention works smoothly... Besides the sign up or sign in process, it requires firebaseinstallations.googleapis.com, I set one alive IP in the hosts. For Signal, maybe hardcode or delivery alive IPs, I'm considering.

[UjuiUjuMandan]

The pcap logs still have Google domains after a while, I guess there must something like cloud configurations, if so please change it too.