Remove unused client_id

[yubiuser]

What does this PR aim to accomplish?:

Fixes an issue that was introduced by #2202.
This PR added a few columns from the query_storage table of the long-term database to the output of web interface. However, one column does not exist (client_id). (Probably a leftover from testing the code).

Using the web interface right now results in this error:

2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127
2022-07-16 14:38:15: (mod_fastcgi.c.421) FastCGI-stderr: PHP Notice:  Undefined index: client_id in /var/www/html/admin/api_db.php on line 127

This PR removes the unused line.

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[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/undefined-array-key-client-id-in-api-db-php/56587/3

[pralor-bot]

This pull request has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/undefined-array-key-client-id-in-api-db-php/56587/5