UI : add a svg icon for the crash cymbal

[Babali42]

In Rock Variation Pattern the crash cymbal has no icon but the midiNote 49 is well configured

See : src/assets/beats/rock/variation.json
See : src/app/ui/pipes/drum-image.pipe.spec.ts line 36 (the last test)
See : https://www.svgrepo.com/vectors/drums/ and look for a crash cymbal in there