[v3-1-test] Fix trigger ui parameter field is dict when param.value is null (#58682)#58899

pierrejeambrun merged 1 commit intov3-1-testapache/airflow:v3-1-testfrom

backport-0adfc5b-v3-1-testapache/airflow:backport-0adfc5b-v3-1-testCopy head branch name to clipboard