Some bugs can be caught earlier if we're warned when `file` or `file.name` is missing

Introduce getFileName in FileUtils to generate fallback names for attachments lacking original file names. This function extracts and sanitizes filenames from URLs, ensuring attachments in AttachmentCarousel have meaningful names even when original names are missing.

Updated AttachmentCarousel to utilize this new utility function.

At this time, the only know case is embedded attachments shared by the Concierge account via drag and drop

Addressed a bug in libs/fileDownload where the intended fallback for filenames was never reached due to `FileUtils.appendTimeToFileName` always providing a return value. This fix refines the filename determination logic, ensuring effective use of fallback mechanisms across various components including AttachmentCarousel, particularly for cases like attachments shared by the Concierge account.

Expensify#31791 (comment)

…loads

# Conflicts:
#	src/components/Attachments/AttachmentCarousel/extractAttachmentsFromReport.js