Delete application_piped_id index

[funera1]

because application_piped_id_updated_at_desc index covers the index.

What this PR does / why we need it:
The application_piped_id_updated_at_desc index covers the index.

Also, DROP INDEX statement should be remove after few releases.

Fixes #

Does this PR introduce a user-facing change?:

NONE

Reference

Before delete application_piped_id index

mysql> EXPLAIN SELECT Data FROM Application WHERE PipedId = "c360ac00-4b59-47b7-803c-f6fa56c8bebf";
+----+-------------+-------------+------------+------+-----------------------------------------------------------+----------------------+---------+-------+------+----------+-------+
| id | select_type | table       | partitions | type | possible_keys                                             | key                  | key_len | ref   | rows | filtered | Extra |
+----+-------------+-------------+------------+------+-----------------------------------------------------------+----------------------+---------+-------+------+----------+-------+
|  1 | SIMPLE      | Application | NULL       | ref  | application_piped_id,application_piped_id_updated_at_desc | application_piped_id | 146     | const |    1 |   100.00 | NULL  |
+----+-------------+-------------+------------+------+-----------------------------------------------------------+----------------------+---------+-------+------+----------+-------+
1 row in set, 1 warning (0.00 sec)**Which issue(s) this PR fixes**:

+----+-------------+-------------+------------+------+-----------------------------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
| id | select_type | table       | partitions | type | possible_keys                                             | key                                  | key_len | ref   | rows | filtered | Extra |
+----+-------------+-------------+------------+------+-----------------------------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
|  1 | SIMPLE      | Application | NULL       | ref  | application_piped_id,application_piped_id_updated_at_desc | application_piped_id_updated_at_desc | 146     | const |    1 |   100.00 | NULL  |
+----+-------------+-------------+------------+------+-----------------------------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
1 row in set, 1 warning (0.00 sec)

After delete application_piped_id index

+----+-------------+-------------+------------+------+--------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
| id | select_type | table       | partitions | type | possible_keys                        | key                                  | key_len | ref   | rows | filtered | Extra |
+----+-------------+-------------+------------+------+--------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
|  1 | SIMPLE      | Application | NULL       | ref  | application_piped_id_updated_at_desc | application_piped_id_updated_at_desc | 146     | const |    1 |   100.00 | NULL  |
+----+-------------+-------------+------------+------+--------------------------------------+--------------------------------------+---------+-------+------+----------+-------+
1 row in set, 1 warning (0.01 sec)