Do Not Show Preview For Unsupported Media Formats

[gasi-signal]

We currently treat unrecognized video formats such as WMV as video attachments even though they can’t be played in Chromium. Update our code to treat them as regular file attachments without preview. This will prompt the user to save them to their file system and play it with an appropriate media player:

• Signal-Desktop/js/views/attachment_view.js

  Lines 138 to 140 in 3ae1752

  	isVideo() {
  	return this.model.contentType.startsWith('video/');
  	},

• Signal-Desktop/js/views/attachment_view.js

  Lines 65 to 69 in 3ae1752

  	// Blacklist common file types known to be unsupported in Chrome
  	const unsupportedFileTypes = [
  	'audio/aiff',
  	'video/quicktime',
  	];

See: #1174 (comment)

[mbeirouti]

Is this issue resolved @gasi-signal? I tested this functionality just now on Windows and I see that a wmv file doesn't have a preview and instead shows up as a downloadable file (top is wmv, bottom is mp4):