[chore] media pipeline improvements (#3110)

* don't set emoji / media image paths on failed download, migrate FileType from string to integer

* fix incorrect uses of util.PtrOr, fix returned frontend media

* fix migration not setting arguments correctly in where clause

* fix not providing default with not null column

* whoops

* ensure a default gets set for media attachment file type

* remove the exclusive flag from writing files in disk storage

* rename PtrOr -> PtrOrZero, and rename PtrValueOr -> PtrOrValue to match

* slight wording changes

* use singular / plural word forms (no parentheses), is better for screen readers

* update testmodels with unknown media type to have unset file details, update attachment focus handling converting to frontend, update tests

* store first instance in ffmpeg wasm pool, fill remaining with closed instances

internal/processing/admin/emoji.go

@@ -325,8 +325,8 @@ func (p *Processor) emojiUpdateCopy(
 
 	// Attempt to create the new local emoji.
 	emoji, errWithCode := p.createEmoji(ctx,
-		util.PtrValueOr(shortcode, ""),
-		util.PtrValueOr(categoryName, ""),
+		util.PtrOrValue(shortcode, ""),
+		util.PtrOrValue(categoryName, ""),
 		data,
 	)
 	if errWithCode != nil {