webhooks: make SGX mutator registration to follow other webhooks

[mythi]

Fixes: #1681

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes are missing coverage. Please review.

Project coverage is 39.67%. Comparing base (ce5bfa4) to head (da81f1b).
Report is 2 commits behind head on main.

❗ Current head da81f1b differs from pull request most recent head cbaedda. Consider uploading reports for the commit cbaedda to get more accurate results

Files	Patch %	Lines
pkg/webhooks/sgx/sgx.go	0.00%	5 Missing ⚠️
cmd/operator/main.go	0.00%	1 Missing ⚠️
cmd/sgx_admissionwebhook/main.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1677      +/-   ##
==========================================
- Coverage   39.71%   39.67%   -0.04%     
==========================================
  Files          73       73              
  Lines        6521     6520       -1     
==========================================
- Hits         2590     2587       -3     
- Misses       3781     3782       +1     
- Partials      150      151       +1     

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[mythi]

get #1681 fixed before merging