history: fix an bugprone-string-integer-assignment instance

`row.normalized_term` is a `string16`, but the RHS here is an int64.
This means the string16 is being assigned to a single-char string, where
the char has a value of: `(uint16_t)statement.ColumnInt64(2)`. This
probably isn't what was intended.

Bug: 1130867
Change-Id: Id7b692a2901514b2f3cd1d5833ce145074b41983
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2424814Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812047}

components/history/core/browser/url_database.cc

@@ -563,7 +563,7 @@ bool URLDatabase::GetKeywordSearchTermRows(
     row.url_id = statement.ColumnInt64(1);
     row.keyword_id = statement.ColumnInt64(0);
     row.term = term;
-    row.normalized_term = statement.ColumnInt64(2);
+    row.normalized_term = statement.ColumnString16(2);
     rows->push_back(row);
   }
   return true;