The invoice extraction feature no longer includes the old setting that limited email attachment extraction to PDFs only. This cleans up configuration screens and database fields after the process was simplified elsewhere, reducing confusion for users.

Problem
--------
Since commit 24345812cb015e86f362f8c35176646239bfb803 (community), we removed the need for `alias_auto_extract_pdfs_only`. This commit removes this field from the database, the views and the tests.

task-3536162