Use MySQL8.4 with utf8mb4

[nanasess]

This pull request includes an update to the MySQL service configuration in the docker-compose.mysql.yml file. The most important change is upgrading the MySQL version and adjusting the character set and collation settings.

MySQL service configuration update:

• docker-compose.mysql.yml: Upgraded MySQL image from mysql:8.0 to mysql:8.4 and changed the character set to utf8mb4 and collation to utf8mb4_general_ci.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.72%. Comparing base (a895209) to head (ebf1770).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1044   +/-   ##
=======================================
  Coverage   51.72%   51.72%           
=======================================
  Files          80       80           
  Lines       10202    10202           
=======================================
  Hits         5277     5277           
  Misses       4925     4925           

Flag	Coverage Δ
tests	51.72% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.