AAP-45589 - add comment for default timeout set up (#738)

## Description
- What is being changed?
Adding missing comment for default timeout
- Why is this change needed?
To improve the code readability 
- How does this change address the issue?
Add a comment with the reason for timeout been 20

## Type of Change
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- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [x] Documentation update
- [ ] Test update
- [ ] Refactoring (no functional changes)
- [ ] Development environment change
- [ ] Configuration change

## Self-Review Checklist
<!-- These items help ensure quality - they complement our automated CI
checks -->
- [ ] I have performed a self-review of my code
- [ ] I have added relevant comments to complex code sections
- [ ] I have updated documentation where needed
- [ ] I have considered the security impact of these changes
- [ ] I have considered performance implications
- [ ] I have thought about error handling and edge cases
- [ ] I have tested the changes in my local environment

## Testing Instructions
### Expected Results
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## Additional Context
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### Required Actions
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- [ ] Requires documentation updates
  <!-- API docs, feature docs, deployment guides -->
- [ ] Requires downstream repository changes
  <!-- Specify repos: django-ansible-base, eda-server, etc. -->
- [ ] Requires infrastructure/deployment changes
  <!-- CI/CD, installer updates, new services -->
- [ ] Requires coordination with other teams
  <!-- UI team, platform services, infrastructure -->
- [ ] Blocked by PR/MR: #XXX
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### Screenshots/Logs
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Author: jay-steurer

ansible_base/authentication/authenticator_plugins/ldap.py

@@ -379,6 +379,7 @@ def __init__(self, prefix: str = 'AUTH_LDAP_', defaults: dict = {}):
 
         # If a DB-backed setting is specified that wipes out the
         # OPT_NETWORK_TIMEOUT, fall back to a sane default
+        # This default should be less than 30 because that is the timeout of envoy
         if ldap.OPT_NETWORK_TIMEOUT not in internal_data:
             internal_data[ldap.OPT_NETWORK_TIMEOUT] = 20