fix(member): handle error in DeleteAllMember to prevent nil pointer p…

[goyalpalak18]

Description

I ran into a crash when using harbor project member delete --all while my Harbor credentials were expired.

Instead of telling me the request failed, the CLI panicked with a nil pointer dereference. It turns out the DeleteAllMember function was ignoring errors from the API and trying to read the empty response anyway.

This PR fixes that by adding proper error checking. Now, if the API call fails (network timeout, 401, etc.), the CLI will print a readable error message and exit cleanly instead of crashing with a stack trace.

Verification

I reproduced this by simulating a network error during the delete command.

• Before: CLI panicked with runtime error: invalid memory address.
• After: CLI printed failed to list members: connection refused and exited with code 1.

Checklist

• Panic is fixed.
• Error messages are readable.
• Verified happy path still works.

[goyalpalak18]

Hi @bupd! Could you please review this fix for the nil pointer panic? Thanks!

[codecov]

Codecov Report

❌ Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 7.17%. Comparing base (60ad0bd) to head (85d12ff).
⚠️ Report is 82 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/api/member_handler.go	0.00%	12 Missing ⚠️
cmd/harbor/root/project/member/delete.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             main    #660      +/-   ##
=========================================
- Coverage   10.99%   7.17%   -3.82%     
=========================================
  Files         173     260      +87     
  Lines        8671   12854    +4183     
=========================================
- Hits          953     922      -31     
- Misses       7612   11824    +4212     
- Partials      106     108       +2     

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