Remove deprecated symbols from rtc_base and p2p

Remove deprecated methods from:
- DtlsTransportInternal
- ByteBufferWriterT
- VirtualSocketServer
- SampleStats
- ProxyBinding
- AsyncProxyServerSocket
- Socket
- SSLAdapter

And some untagged Subscribe methods from Connection,
IceTransportInternal, Port, PortInterface, and
PortAllocator

Bug: webrtc:465197113, webrtc:42225170, webrtc:42224904
Change-Id: Idf44ea082d561f43162144337c18e6a17f18ee50
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/482761
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Auto-Submit: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#48025}