chore(python): Reduce posthog event count (#661)

- Register open_table as event
- Because we're dropping 'seach' event currently, changed the name to
'search_table' and introduced throttling
- Throttled events will be counted once per time batch so that the user
is registered but event count doesn't go up by a lot

python/lancedb/table.py

@@ -899,6 +899,8 @@ class LanceTable(Table):
                 f"Table {name} does not exist."
                 f"Please first call db.create_table({name}, data)"
             )
+        register_event("open_table")
+
         return tbl
 
     def delete(self, where: str):