Add 0.5s mp3 redirectable resource

Command used to generate 0.5s mp3 file:

ffmpeg -ar 48000 -t 0.5 -f s16le -acodec pcm_s16le -ac 2 -i /dev/zero -acodec libmp3lame -aq 4 noop-0.5s.mp3

Related filter issue:
- https://github.com/uBlockOrigin/uAssets/issues/14231

src/js/redirect-engine.js

@@ -144,6 +144,8 @@ const redirectableResources = new Map([
         alias: [ 'noopmp3-0.1s', 'abp-resource:blank-mp3' ],
         data: 'blob',
     } ],
+    [ 'noop-0.5s.mp3', {
+    } ],
     [ 'noop-1s.mp4', {
         alias: 'noopmp4-1s',
         data: 'blob',