Improve meta query for tags

ui/src/shared/apis/v2/queryBuilder.ts

@@ -38,11 +38,15 @@ async function findKeys(
 
   const query = `from(bucket: "${bucket}")
   |> range(start: -${SEARCH_DURATION})${tagFilters}
-  |> drop(columns: ["_time", "_start", "_stop", "_value"])
   |> keys()
   |> group()
   |> distinct()
   |> keep(columns: ["_value"])${searchFilter}${previousKeyFilter}
+  |> filter(fn: (r) =>
+        r._value != "_time" or
+        r._value != "_start" or
+        r._value !=  "_stop" or
+        r._value != "_value")
   |> sort()
   |> limit(n: ${LIMIT})`