"Illegal mix of collations" error when using CSV Static Endpoint for queries with emojis

[shuttie]

Describe the bug
When I create a CSV Static File endpoint with a CSV file having queries with UTF surrogate pairs (e.g. emojis), import fails:

[75432bc3-6079-4423-8949-020bdc6d7abb] Completed 500 Internal Server Error in 15ms (ActiveRecord: 7.5ms | Allocations: 2639)
[75432bc3-6079-4423-8949-020bdc6d7abb]   
[75432bc3-6079-4423-8949-020bdc6d7abb] ActiveRecord::StatementInvalid (Mysql2::Error: Illegal mix of collations (utf8mb3_general_ci,IMPLICIT) and (utf8mb4_bin,COERCIBLE) for operation '='):

A sample file reproducing the issue: kfc.csv
Where the query is kfc 🍟➕🍔➕🍗 - yes I also wonder who searches like that, but here we are.

To Reproduce
Steps to reproduce the behavior on v7.17.1:

1. Go to Relevance Cases > Create case
2. Click on 'CSV Static Endpoint' and upload sample file (or any other with surrogate pairs)
3. Click 'import',
4. UI hangs, and in console there's Mysql2::Error: Illegal mix of collations error.

Expected behavior
Expected the UI and import not to break on such weird queries.

[epugh]

Just tested this, and yeah:

ActiveRecord::StatementInvalid (Mysql2::Error: Illegal mix of collations (utf8mb3_general_ci,IMPLICIT) and (utf8mb4_bin,COERCIBLE) for operation '=')
Caused by: Mysql2::Error (Illegal mix of collations (utf8mb3_general_ci,IMPLICIT) and (utf8mb4_bin,COERCIBLE) for operation '=')

Information for: ActiveRecord::StatementInvalid (Mysql2::Error: Illegal mix of collations (utf8mb3_general_ci,IMPLICIT) and (utf8mb4_bin,COERCIBLE) for operation '='):

Sorry it's taken so long to get to this, I somehow missed it after having just a quick glance. Working on this now for upcoming Quepid8 release.

[shuttie]

Thanks @epugh - as a millennial myself, never thought that people might use emojis as a search query 🍔 . but here we are.