Cube Store readily ingests CSV files with non-unique columns

**Describe the bug**
Cube Store loads a CSV file with pre-aggregated data and stores it without errors even if it contains non-unique columns (e.g., two columns with identical names).

**To Reproduce**
Steps to reproduce the behavior:
1. Create a pre-aggregation where a single dimension is references twice
2. Execute a query and trigger pre-aggregations build
3. The query will yield this error:
> Internal: Error during planning: Schema contains duplicate qualified field name "..."

**Expected behavior**
Cube Store fails to ingest data with non-unique columns and shows an error message clearly indicating the issue.

**Screenshots**

**Version:**
0.28.38