Show a message when an e-document file cannot be viewed or no data could be extracted

[Explorer986]

What & why

When a Payables Agent e-document came from a file that is not a valid invoice, or a corrupt PDF, clicking View PDF or View extracted data threw a runtime error. This adds small guards so both actions show a clear message when there is nothing to display or the file cannot be read.

Linked work

Fixes AB#638785

How I validated this

• I read the full diff and it contains only changes I intended.
• I built the affected app(s) locally with no new analyzer warnings.
• I ran the change in Business Central and confirmed it behaves as expected.
• I added or updated tests for the new behavior, or explained below why none are needed.

What I tested and the outcome

• Corrupt PDF: View PDF now shows "the file cannot be displayed" message instead of the client render error.
• Valid non-invoice PDF: View extracted data shows a clear "no extracted data" message, and View PDF still opens the file.
• Normal invoice: both views work as before.

Risk & compatibility

Low. Only adds guards and user messages on two view actions. No schema, data, or permission impact.