[Bug] Fix Qwen3-Embedding model loading

[reidliu41]

Essential Elements of an Effective PR Description Checklist

• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
• The test plan, such as providing test command.
• The test results, such as pasting the results comparison before and after, or e2e results
• (Optional) The necessary documentation update, such as updating supported_models.md and examples for a new model.

Purpose

fixes: #21614

Test Plan

Test Result

(Optional) Documentation Update

[gemini-code-assist]

Code Review

This pull request adds support for loading Qwen3-Embedding models by registering the model and adding logic to handle weight prefixes. I've identified a critical bug in the load_weights implementation that will cause a crash when loading models that already have the correct weight prefix. A fix has been suggested.

[github-actions]

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[reidliu41]

cc @noooop

[noooop]

I'm sorry, I think this error is caused by #21227 and should be fixed by #21470.

[reidliu41]

ok, got it