fix(metrics): Remove Home/End key handlers from metric selector search input

Home and End keys were intercepted and prevented from propagating to the
search input, breaking cursor navigation to the start/end of typed text.
Since the input always retains DOM focus via virtual focus, these keys
should be passed through to the input element unchanged.

Co-Authored-By: Claude Sonnet 4 <noreply@example.com>

Author: nsdeschenes

static/app/views/explore/metrics/metricToolbar/metricSelector.tsx

@@ -420,26 +420,6 @@ export function MetricSelector({
         }
         return;
       }
-
-      if (e.key === 'Home') {
-        e.preventDefault();
-        manager.setFocused(true);
-        const firstKey = collection.getFirstKey();
-        if (firstKey !== null) {
-          manager.setFocusedKey(firstKey);
-        }
-        return;
-      }
-
-      if (e.key === 'End') {
-        e.preventDefault();
-        manager.setFocused(true);
-        const lastKey = collection.getLastKey();
-        if (lastKey !== null) {
-          manager.setFocusedKey(lastKey);
-        }
-        return;
-      }
     },
     [focusedKey, displayedOptionsMap, handleSelect, listState]
   );