fix(shell): Take a bigger margin for terminal size

[erebe]

Summary

When openning the shell websocket, the frontend compute the width and height of the terminal to forward it to the backend.
Today, the width and height are too big causing line wrapping

• Use the shell container size instead of the global one
• increase the cell height to avoid line wrapping

Before

After

[codecov]

Codecov Report

❌ Patch coverage is 89.28571% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.21%. Comparing base (87e33c3) to head (9aed8ec).

Files with missing lines	Patch %	Lines
...use-terminal-dimensions/use-terminal-dimensions.ts	88.46%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           staging    #2811      +/-   ##
===========================================
- Coverage    47.60%   47.21%   -0.39%     
===========================================
  Files          783     1176     +393     
  Lines        19626    25439    +5813     
  Branches      5954     7544    +1590     
===========================================
+ Hits          9342    12010    +2668     
- Misses        8635    11390    +2755     
- Partials      1649     2039     +390     

Flag	Coverage Δ
unittests	47.21% <89.28%> (-0.39%)	⬇️

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