Enable TLS 1.3 in dnsproxy

[ameshkov]

It seems that we have not yet enabled TLS 1.3 in the mobile dnsproxy build.

We should do it.

Test server:
https://dns.glassrom.pw/dns-query

[admitrevskiy]

Done.

Testing instructions for QA:

• Reinstall AG
• Check if https://dns.glassrom.pw/dns-query is available using dnslookup
• Try to add custom DNS server with https://dns.glassrom.pw/dns-query upstream