refactor(core): Remove unused definitions from ua_securechannel.h
refactor(core): Remove unused definitions from ua_securechannel.h

JGrothoff/open62541,StalderT/open62541,jpfr/open62541,JGrothoff/open62541,JGrothoff/open62541,open62541/open62541,jpfr/open62541,StalderT/open62541,open62541/open62541,open62541/open62541,jpfr/open62541,JGrothoff/open62541,StalderT/open62541,jpfr/open62541,open62541/open62541,StalderT/open62541