cerry pick (fake)TLS ClientHello changes from upstream

[zolg]

Russian censorship DPI blocks traffic to MTProto proxies by detecting anomalies in TLS ClientHello sent by Telegram client.

Details and quick but working solution here: DrKLO#1949
Changes from this pull request was implemented in 12.6.4 (6666)
DrKLO@009e973 (TMessagesProj/jni/tgnet/ConnectionSocket.cpp)

please either merge pr above, or cherry-pick upstream changes

[zolg]

Thank you very much.
I can confirm that the proxy works properly in ForkClient.12.6.5.0.apk