upload-sarif: `git call failed.` more times than necessary for a working directory without a git repository

Start in src/git-utils.ts at the referenced line and compare its behavior with the linked workflow log. Trace why a missing repository causes repeated git calls during upload-sarif, then verify that the action still uploads SARIF successfully without repeatedly issuing those calls when no repository is checked out.

https://github.com/github/codeql-action/blob/f67ec12472e1b361f5e1e2085f5e6f85a57e3cd6/src/git-utils.ts#L87

https://github.com/check-spelling-sandbox/skipper/actions/runs/20649925837/job/59292941788

Run github/codeql-action/upload-sarif@7434149006143a4d75b82a2f411ef15b03ccc2d7
git call failed. Continuing with commit SHA from user input or environment. Error: The checkout path provided to the action does not appear to be a git repository.
Uploading code scanning results
  Processing sarif files: ["cifuzz-sarif/results.sarif"]
  Validating cifuzz-sarif/results.sarif
  Adding fingerprints to SARIF file. See https://docs.github.com/en/enterprise-cloud@latest/code-security/code-scanning/integrating-with-code-scanning/sarif-support-for-code-scanning#providing-data-to-track-code-scanning-alerts-across-runs for more information.
  (node:12002) [DEP0169] DeprecationWarning: `url.parse()` behavior is not standardized and prone to errors that have security implications. Use the WHATWG URL API instead. CVEs are not issued for `url.parse()` vulnerabilities.
  (Use `node --trace-deprecation ...` to show where the warning was created)
  git call failed. Continuing with commit SHA from user input or environment. Error: The checkout path provided to the action does not appear to be a git repository.
  git call failed. Continuing with commit SHA from user input or environment. Error: The checkout path provided to the action does not appear to be a git repository.
  git call failed. Will calculate the base branch SHA on the server. Error: The checkout path provided to the action does not appear to be a git repository.
  Uploading results
  Successfully uploaded results
Waiting for processing to finish
git call failed. Continuing with commit SHA from user input or environment. Error: The checkout path provided to the action does not appear to be a git repository.

Ideally, the action should be able to "quickly" determine that there isn't a repository checked out and not waste additional time running git commands.

Note that this flow (using google/clusterfuzzlite/actions/run_fuzzers and then ideally uploading sarif output) is a flow that people expect to be able to do (yes, Google is missing documentation for how to do it, but...).