Remove Line Numbers from Bill PDF Scraping

## Summary

We just added a new codepath to scrape the Document text of a "Bill" from the legislature-provided PDF as a fallback for when the legislature doesn't make that text available via the API's `content.DocumentText` field.

It looks like this is working reasonably well, but we've just noticed an issue in one particular case: in addition to the text of the bill, we are also scraping the line numbers (which is technically legible, but looks noticeably off).

To remedy this, we should filter out line number when scraping the text from a bill's PDF.

## Success Criteria
- [ ] PDF-scraped text should also filter out line numbers
- [ ] Existing successful text scraping should be unaffected

## Additional Links
- Example bill that hit this issue: https://maple-dev.vercel.app/bills/194/H5469
- This has a `DocumentText` of `null` in the API, so it will use the PDF fallback, but we have also scraped line numbers (visible if you go to the page and click "View Text" to open the bill text modal).

@Smoss Related to your recent work on PDF scraping