Change CodeDeploy config file permissions to owner only

[aahallal]

Changed the CodeDeploy on-premises instance configuration file creation to use os.open() with explicit permissions (0o600) instead of the default open() function. This ensures the configuration file is created with owner-only read/write permissions, improving security by preventing other users on the system from accessing potentially sensitive configuration data.

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.43%. Comparing base (c4681b5) to head (81e598b).
⚠️ Report is 261 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #10206      +/-   ##
===========================================
+ Coverage    93.39%   93.43%   +0.04%     
===========================================
  Files          210      210              
  Lines        17052    17241     +189     
===========================================
+ Hits         15925    16109     +184     
- Misses        1127     1132       +5     

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