h5n1-cattle-outbreak: loosen genome_clock_filter_iqd

Loosening the genome_clock_filter_iqd because the important human
sequences have been filtered out by the clock filter in the latest
builds.

<https://bedfordlab.slack.com/archives/CD84ELG0N/p1735438616520059>

config/h5n1-cattle-outbreak.yaml

@@ -76,7 +76,7 @@ refine:
   date_inference: marginal
 
   genome_clock_filter_iqd:
-    FALLBACK: 3
+    FALLBACK: 2
   clock_filter_iqd:
     FALLBACK: false