update default processor for unknwon type config

[MinerYang]

Thank you for contributing to Harbor!

Comprehensive Summary of your change

Issue being fixed

Fixes #19175

Please indicate you've done the following:

• Well Written Title and Summary of the PR
• Label the PR as needed. "release-note/ignore-for-release, release-note/new-feature, release-note/update, release-note/enhancement, release-note/community, release-note/breaking-change, release-note/docs, release-note/infra, release-note/deprecation"
• Accepted the DCO. Commits without the DCO will delay acceptance.
• Made sure tests are passing and test coverage is added if needed.
• Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov]

Codecov Report

Merging #19372 (653c916) into main (50e466b) will increase coverage by 0.00%.
The diff coverage is 15.38%.

@@           Coverage Diff           @@
##             main   #19372   +/-   ##
=======================================
  Coverage   67.45%   67.46%           
=======================================
  Files         988      988           
  Lines      108688   108688           
  Branches     2752     2752           
=======================================
+ Hits        73316    73321    +5     
+ Misses      31431    31420   -11     
- Partials     3941     3947    +6     

Flag	Coverage Δ
unittests	67.46% <15.38%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
src/controller/artifact/processor/default.go	54.76% <8.33%> (-16.67%)	⬇️
src/server/middleware/subject/subject.go	49.31% <100.00%> (ø)

... and 10 files with indirect coverage changes

[zyyw]

We may also need to add this to this PR:

• https://github.com/goharbor/harbor/pull/19367/files#diff-e600b4a9acca6ebd3c99f257f5f44aa7a387e5220ccd87eda5fe84f1c400fa04

w.Header().Set("OCI-Subject", subjectArt.Digest)
->
w.Header().Set("OCI-Subject", mf.Subject.Digest.String())

[MinerYang]

We may also need to add this to this PR:

* https://github.com/goharbor/harbor/pull/19367/files#diff-e600b4a9acca6ebd3c99f257f5f44aa7a387e5220ccd87eda5fe84f1c400fa04

w.Header().Set("OCI-Subject", subjectArt.Digest)
->
w.Header().Set("OCI-Subject", mf.Subject.Digest.String())

True. thx

[wy65701436]

lgtm