Update snippet RRD: howto/load_mcap.rrd (#11201)

### What

Updates the rrd used for backwards compatability testing.

- [x] pass `@rerun-bot full-check`

Author: oxkitsune

tests/assets/rrd/snippets/howto/load_mcap.rrd

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:18a778ee5bfc9e870665be434c45ccfacd9d4ee9193ab17cae6106cfbf7a3e88
-size 38542346
+oid sha256:78ece4548cbf05abd059dc5d40f8714b41fa652fbe6ba96acabb477087feb9fc
+size 19415294