fix(core): Reset sequence numbers in UA_SecureChannel_close #1091

Job	Run time
Debug Build & Unit Tests (gcc)	1m 46s
Debug Build & Unit Tests without Subscriptions (gcc)	46s
Debug Build & Unit Tests with Diagnostics (gcc)	1m 46s
Debug Build & Unit Tests with multithreading (gcc)	1m 36s
Debug Build & Unit Tests with Alarms&Conditions (gcc)	2m 41s
Debug Build & Unit Tests (clang)	2m 26s
Debug Build & Unit Tests (tcc)	1m 34s
Encryption (MbedTLS) Build & Unit Tests (gcc)	1m 18s
PubSub Encryption (MbedTLS) Build & Unit Tests (gcc)	1m 38s
Encryption (OpenSSL) Build & Unit Tests (gcc)	1m 14s
Encryption (LibreSSL) Build & Unit Tests (gcc)	3m 42s
TPM Tool Build	2m 0s
Release Build	48s
Amalgamation Build	33s
Amalgamation Build with Multithreading	39s
Valgrind Unit Tests with MbedTLS (gcc)	5m 38s
Valgrind Unit Tests with OpenSSL (gcc)	5m 35s
Valgrind Examples with MbedTLS (gcc)	10m 56s
Valgrind Examples with OpenSSL (gcc)	11m 0s
Clang Static Analyzer	2m 19s
	59m 55s

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