Refactoring: Simplify upload SARIF flow and reuse loaded flags

[henrymercer]

Minor refactoring to simplify the flow for uploading SARIF files, and to reuse the loaded feature flags if we've already loaded them from disk or from the API.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Confirm the readme has been updated if necessary.
• Confirm the changelog has been updated if necessary.

[aeisenberg]

Looks like a general improvement, but just want to make sure about the payload change.

[aeisenberg]

Previously, this was analysisName, but that doesn't look right since the util.getRequiredEnvParam("GITHUB_WORKFLOW") was being passed in. Now you're using category. This seems to be correct now, but will that mess up anything with our teleemtry since we're changing what we're stuffing into the analysis_name field of the payload?

[henrymercer]

You're right, let's keep it the same. My understanding is the category in the SARIF overrides what we have in the analysis_name field, and GITHUB_WORKFLOW gives the job name, which we could use as a fallback. We might be able to stop specifying the analysis_name field if we're sure we're always specifying a category in the SARIF, but I'll leave that cleanup for later.

[angelapwen]

💭 The submit SARIF after failure workflow on main seems to be failing now after this was merged 😢 (though I'm not sure why it didn't fail in this PR's checks).

[aeisenberg]

The latest run on main is passing, but I see the run associated with #2364 is failing. I'm rerunning since it might be transient.

[aeisenberg]

...and it passed! So, guessing the error came from the server side.

[henrymercer]

This was due to an internal experiment on the API endpoints (unrelated to this PR). The relevant feature flag is now disabled. I've cced you in Slack.