issue 8649: host_pods should not be mandatory to node-agent

[mpryc]

Fixes #8649. The host_pods path should not be mandatory for node-agent.

This update enables the node-agent to start even if the /host_pods path does not exist. If the path is present, the existing logic remains unchanged, ensuring it is readable.

This PR does not address mounting (or omitting) the /host_pods directory.

Additionally, this change specifically resolves #8649 and not #8185, which requires further design work and will be handled in a separate PR.

[kaovilai]

Don't be alarmed about e2e tests.. unrelated to PR #8766

[codecov]

Codecov Report

Attention: Patch coverage is 28.57143% with 5 lines in your changes missing coverage. Please review.

Project coverage is 59.53%. Comparing base (1516e72) to head (3262b86).

Files with missing lines	Patch %	Lines
pkg/cmd/cli/nodeagent/server.go	28.57%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8774      +/-   ##
==========================================
- Coverage   59.53%   59.53%   -0.01%     
==========================================
  Files         371      371              
  Lines       40196    40200       +4     
==========================================
  Hits        23932    23932              
- Misses      14767    14771       +4     
  Partials     1497     1497              

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