chore(ct): add flag to mark ct_entry connection direction is unkown

[SRodi]

Description

• add new member is_direction_unknown to conntrack_entry struct
• set is_direction_unknown to true when the SYN packet is not captured

Related Issue

#919

Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• I have correctly attributed the author(s) of the code.
• I have tested the changes locally.
• I have followed the project's style guidelines.
• I have updated the documentation, if necessary.
• I have added tests, if applicable.

Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes made.

Additional Notes

Add any additional notes or context about the pull request here.

---

Please refer to the CONTRIBUTING.md file for more information on how to contribute to this project.

[timraymond]

This looks fine to me, but I also want @nddq to approve.