Add errno label to fuse ops metric

[polyrabbit]

Senario:

1. Better understanding users' pattern
2. Set up alarm rules on abnormal error rate

[codecov]

Codecov Report

Attention: Patch coverage is 92.85714% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 53.57%. Comparing base (b281022) to head (4167043).
Report is 7 commits behind head on main.

❗ Current head 4167043 differs from pull request most recent head bcdfbb1. Consider uploading reports for the commit bcdfbb1 to get more accurate results

Files	Patch %	Lines
pkg/vfs/internal.go	0.00%	0 Missing and 1 partial ⚠️
pkg/vfs/vfs.go	96.55%	1 Missing ⚠️
pkg/vfs/vfs_unix.go	85.71%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #4656       +/-   ##
===========================================
+ Coverage   24.97%   53.57%   +28.59%     
===========================================
  Files          25      124       +99     
  Lines       15994    33547    +17553     
===========================================
+ Hits         3995    17973    +13978     
- Misses      11512    13405     +1893     
- Partials      487     2169     +1682     

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