Avoid re-connecting every Ctrl+C (bugfix)

[Hook25]

Description

This is a weird behaviour because regardless of what the user picks from the ctrl+c menu, we will always re-connect from scratch and sometimes mess up the session

Resolved issues

N/A (Ctrl+C didnt work, with this patch it does)

Documentation

N/A

Tests

Tested locally, before this patch, Ctrl+C always reconnects, so it basically never works.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.87%. Comparing base (03581f9) to head (72d7c1c).
⚠️ Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
checkbox-ng/checkbox_ng/launcher/controller.py	0.00%	15 Missing ⚠️

❌ Your patch check has failed because the patch coverage (0.00%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2463   +/-   ##
=======================================
  Coverage   58.86%   58.87%           
=======================================
  Files         476      476           
  Lines       48007    48002    -5     
  Branches     8570     8568    -2     
=======================================
  Hits        28260    28260           
+ Misses      18855    18851    -4     
+ Partials      892      891    -1     

Flag	Coverage Δ
checkbox-ng	76.05% <0.00%> (+0.01%)	⬆️

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[fernando79513]

Please add a more detailed description of what the behavior was before this PR, and how this solves the issue.
I tried to run smoke tests with the previous version with:

checkbox.checkbox-cli control 10.164.173.184 smoke_launcher 

And I was able to continue the execution, disconnect from the agent, and start a new one.

[fernando79513]

Thanks for taking care of this.

I think this PR could benefit greatly from some metabox tests. I don't know how difficult it would be to add them, but I think they can help us avoid these kinds of issues in the future.

[fernando79513]

I run the metabox tests manually yesterday and they are failing:
https://github.com/canonical/checkbox/actions/runs/24726686275/job/72329566224