Google Sheets Plugin - Sync only doesn't handle duplicate headers

[djohalo2]

Describe the bug
The Google Sheets Plugin mostly handles duplicate headers by generating unique headers in all places except when running a sync only.

To Reproduce
Steps to reproduce the behavior:

1. Create a Google Sheet with duplicate column headers, for example: Name, Status, Status.
2. Open the CMS plugin
3. Configure the two Status columns with different field types or mappings.
4. Import the sheet successfully once
5. Update a value in the second duplicate column.
6. Run a sync-only update for the collection
7. Observe that the second duplicate column does not reliably use its own stored configuration; it is matched using the raw duplicate header instead of its generated unique column ID.

Expected behavior
It should generate unique header names when syncing the sheet using the 'sync' button.

Screenshots
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Additional context
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