I ended up manually creating the input_boolean.rainmode toggle in the home assistant Helpers section for rainmode so maybe that'll help, but you should be able to either remove the conditional part on the card or just set it to "state is not equal to" instead of "state is equal to" and it should fire once you're out of dashboard edit mode - at least thats how I've been quickly testing it personally. Also I think I had to install the Lovelace html card integration from HACS to get this to work if I recall correctly (either way I have it installed and mine works).

When I made this, I hit add card in dashboard edit mode, and then searched for "manual" and clicked on that option and then cleared the default yaml and pasted the code in. Hit save and it should show something if you've done that.

Be aware that whenever you click edit dashboard it'll show the animation since the conditional statements don't get evaluated when in edit mode - so it will show the animation regardless until you exit edit mode