Dependabot Runs successfully, Fails to create PR with /git/trees: 422 - GitRPC::BadObjectState

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Package ecosystem

https://github.com/actions/runner-images/blob/ubuntu22/20240721.1/images/ubuntu/Ubuntu2204-Readme.md

### Package manager version

Pip3 22.0.2

### Language version

python 3.12.x

### Manifest location and content before the Dependabot update

[/pip-requirements.txt](https://github.com/microsoft/mu_tiano_platforms/blob/main/pip-requirements.txt)

### dependabot.yml content

[dependabot.yml](https://github.com/microsoft/mu_tiano_platforms/blob/main/.github/dependabot.yml)

### Updated dependency

+-------------------------------------------------------------+
| Changes to Dependabot Pull Requests |
+---------+---------------------------------------------------+
| created | edk2-pytool-library ( from 0.21.5 to 0.21.8 ) |
| created | edk2-pytool-extensions ( from 0.27.4 to 0.27.10 ) |
+---------+---------------------------------------------------+

### What you expected to see, versus what you actually saw

Dependabot runs with success, and it lists the correct PRs to update, but fails to create the PR, and shows an error message 3 minutes after the run completes. The error message is below.

Dependabot failed to create a pull request
Dependabot ran into an issue when attempting to create the pull request

Dependabot encountered the following error:

POST https://api.github.com/repos/microsoft/mu_tiano_platforms/git/trees: 422 - GitRPC::BadObjectState // See: https://docs.github.com/rest/git/trees#create-a-tree
[Troubleshoot Dependabot errors](https://docs.github.com/github/managing-security-vulnerabilities/troubleshooting-dependabot-errors)

### Native package manager behavior

No issues.

### Images of the diff or a link to the PR, issue, or logs

https://github.com/microsoft/mu_tiano_platforms/actions/runs/10073577332/job/27847909464

### Smallest manifest that reproduces the issue

_No response_

Start with the linked workflow logs, .github/dependabot.yml, and pip-requirements.txt, then trace the failed POST to /git/trees and the GitRPC::BadObjectState response. Compare the successful update calculation with the PR-creation step; done means the listed pip updates create Dependabot pull requests without the 422 error.

Written by the indexing model from the issue text.