[Bug][framework] First ever converter run bootstraps into incremental mode and silently skips the entire collected backlog

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/incubator-devlake/issues?q=is%3Aissue) and found no similar issues.

### What happened

Fresh install, connected github with appriopriate scopes to pull CI history, ran the blueprint & CI result sets were empty.

### What do you expect to happen

Initial run of a converter that has never ran before should perform a full sync of collected data, regardless of the collectors state.

### How to reproduce

1. Fresh install of `v1.0.3-beta15` (empty database).
2. Add a GitHub connection + scope with CICD entities enabled, on a repo with GitHub Actions history
3. Run the blueprint once, let it finish
4. Observe: `_tool_github_runs` is populated, task log shows `Convert Workflow Runs ... records processed: 0`, and `select count(*) from cicd_pipelines` returns 0. Same for `_tool_github_releases` vs `cicd_releases`.

### Anything else

Only on first install

### Version

v1.0.3-beta15

### Are you willing to submit PR?

- [x] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)