Improve pdf download

[salihozkara]

Resolves https://github.com/volosoft/vs-internal/issues/6542
From now on, only the admin will be able to generate PDFs. If a PDF exists, a download option will be shown in the UI

[oykuermann]

• We can change 'in' with 'to' : PDF generation has started. Once completed, you can check if the file has been added to the PDF files section.
• We don't need to write 'PDF generation started' two times.

• We can't see PDF file before reopening the modal:

screen-capture.-.2025-05-20T114448.491.webm

[oykuermann]

I approved, but please do not merge until vs-internal part is solved:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 52.23%. Comparing base (4a329d1) to head (ff66c09).
Report is 522 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #22922      +/-   ##
==========================================
- Coverage   52.30%   52.23%   -0.08%     
==========================================
  Files        3204     3208       +4     
  Lines      103280   103569     +289     
  Branches     7855     7878      +23     
==========================================
+ Hits        54017    54095      +78     
- Misses      47620    47829     +209     
- Partials     1643     1645       +2     

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