Fix label formatting in user story issue workflow and script

- Updated the label from 'source:qa-tracker' to 'source-qa-tracker' in both the GitHub workflow and the user story issue candidate script for consistency and accuracy.

Author: mossy426-cdc

.github/workflows/user-story-issues.yml

@@ -97,7 +97,7 @@ jobs:
                 color: '0e8a16',
                 description: 'Expected behavior user story',
               },
-              'source:qa-tracker': {
+              'source-qa-tracker': {
                 color: '1d76db',
                 description: 'Generated from MicrobeTrace QA tracker CSVs',
               },

scripts/user_story_issue_candidates.py

@@ -290,7 +290,7 @@ def build_issue(row, repository: str, branch: str, commit_sha: str, actor: str):
         "generated_end": GENERATED_END,
         "labels": [
             "[issue-type] user story",
-            "source:qa-tracker",
+            "source-qa-tracker",
             "needs-review",
         ],
         "epic": epic,