Don't take ownership of data when using `AsyncSigner`; use a reference instead

[brogdonm]

Changes in this pull request

Give a narrative description of what has been changed.

During use of the AsyncSigner trait, we noticed the sign method has a different signature than the simple Signer trait. The current implementation passed ownership of the data to the signer instead of passing a reference.

Checklist

• [X] This PR represents a single feature, fix, or change.
• [ ] All applicable changes have been documented.
• [ ] Any TO DO items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment.

[brogdonm]

@mauricefisher64 @gpeacock The vulnerability failure appears after merging the latest main into this branch.