Remove MySQL specific query from hook_uninstall

Problem/Motivation

It's impossible to uninstall module if the database backend is other then MySQL compatible. Attempt will result in:

$drush config:import -y
+------------+-------------------------------------+-----------+
| Collection | Config                              | Operation |
+------------+-------------------------------------+-----------+
|            | core.extension                      | Update    |
|            | search_api_attachments.admin_config | Delete    |
+------------+-------------------------------------+-----------+

 // Import the listed configuration changes?: yes.                                                                      

 [error]  SQLSTATE[42601]: Syntax error: 7 ERROR:  syntax error at or near "OPTIMIZE"
LINE 1: OPTIMIZE TABLE key_value
        ^: OPTIMIZE TABLE key_value; Array
(
)
 

Proposed resolution

Remove \Drupal::database()->query('OPTIMIZE TABLE key_value')->fetchAll(); line from search_api_attachments_uninstall() function.

Remaining tasks

1. Patch
2. Review
3. Commit

User interface changes

None

API changes

None

Data model changes

None