fix: type error in embedding_bag

[zewenli98]

Description

There's a type error bug in embedding_bag implementation. This is a fix to the PR #2395

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[gs-olive]

Looks good to me, and seems to be validated via CI. Approved, pending CI passes.