Scan fails since #29694

[astellingwerf]

What would you like help with?

I think I found a bug

How are you running Renovate?

Self-hosted

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

37.412.2

Please tell us more about your question or problem

If dependencyDashboard is enabled and the baseBranches are configured but not pointing to any exist branch, then the scan will fail, because packageFiles will in those conditions be null.
See #29694 and https://github.com/astellingwerf/renovate-discussion-29763

Logs (if relevant)

Logs

 INFO: Renovate is exiting with a non-zero code due to the following logged errors
       "loggerErrors": [
         {
           "name": "renovate",
           "level": 50,
           "logContext": "11056169",
           "repository": "dctm/platform/dms",
           "err": {
             "message": "Cannot convert undefined or null to object",
             "stack": "TypeError: Cannot convert undefined or null to object\n    at Function.entries (<anonymous>)\n    at ensureDependencyDashboard (/usr/local/renovate/lib/workers/repository/dependency-dashboard.ts:235:45)\n    at Object.renovateRepository (/usr/local/renovate/lib/workers/repository/index.ts:103:40)\n    at processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at attributes.repository (/usr/local/renovate/lib/workers/global/index.ts:218:11)\n    at start (/usr/local/renovate/lib/workers/global/index.ts:203:7)\n    at /usr/local/renovate/lib/renovate.ts:18:22"
           },
           "msg": "Repository has unknown error",
           "trace_id": "fb9cdd7a2ed99e4a8410baa26f82818a",
           "span_id": "064505d7c8dac1d8",
           "trace_flags": "01"
         }
       ],

[rarkins]

#29765