ui: Do not warn when no reaction to redact was found

The `handle_reaction_redaction` method is called by `handle_redaction`
for every single redaction event that we receive as a first step to
check if the redaction matches a reaction.
It means that not finding a reaction to redact is perfectly fine and is not worthy of a warning.

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

crates/matrix-sdk-ui/src/timeline/event_handler.rs

@@ -906,7 +906,6 @@ impl<'a, 'o> TimelineEventHandler<'a, 'o> {
             }
         }
 
-        warn!("Reaction to redact was missing from the reaction or user map");
         false
     }