tests: net: all: Ensure TLS sockets are built with CID support

Some CID-related functionalities of the DTLS sockets are conditionally
compiled, make sure that code is built with tests/net/all test suite.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

tests/net/all/prj.conf

@@ -17,6 +17,7 @@ CONFIG_MBEDTLS_BUILTIN=y
 CONFIG_MBEDTLS_ENABLE_HEAP=y
 CONFIG_MBEDTLS_HEAP_SIZE=60000
 CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=2048
+CONFIG_MBEDTLS_SSL_DTLS_CONNECTION_ID=y
 
 # net_buf/pkt options
 CONFIG_NET_BUF=y