Hi Shaan,
In your Syslog configuration, you didn't specify the external server to which the logs need to be sent. Rather you've configured it to save the Syslog locally onto the SRX.
You need to include the below line to send the system logs to the external server.
Syntax:
user@host# set system syslog host <IP address> <facility> <severity>
user@host# commit
Example:
user@host# set system syslog host 192.168.11.1 any any
user@host# commit
NOTE: 192.168.11.1 is the IP address of my External Syslog server where I would like to receive the logs.
Second, I reviewed your traffic logging configuration as well and you've missed a line. Please include the following line and let me know the behavior.
Example:
user@host# set security log stream FI_Syslog category all
Please initiate the traffic for the appropriate policy where the session-init and session-close are configured. So, that we can verify the traffic logs.
Let me know if you've any queries.