Cannot override PHP_EXTENSIONS environment variable

[Axel29]

Preconditions

1. Generate a docker-compose.yml file with the following command:
   ./vendor/bin/ece-docker 'build:compose' --with-entrypoint --with-xdebug --set-docker-host --no-os --db='10.4' --php='7.4' --redis='6.0' --expose-db-port=3307 --mode=developer --sync-engine=native --es='7.11' --rmq='3.9''

Steps to reproduce

1. Create a docker-compose.override.yml file
2. Override the generic service environment variables to add imagick to the PHP_EXTENSIONS list
3. Log into the container with bin/magento-docker bash
4. Output the environment variable with a echo $PHP_EXTENSIONS

Expected result

1. The PHP_EXTENSIONS should contain imagick

Actual result

1. The PHP_EXTENSIONS matches the docker-compose.yml file and not the overridden one.

Additional information

If the docker-compose.yml file is updated to add imagick, then it works, which proves that the docker-compose.override.yml isn't taken into account for these environment variable.

I also had the same issue with the SENDMAIL_PATH=/usr/local/bin/mhsendmail --smtp-addr=mailhog:1025 environment variable that I was forced to declare in the original docker-compose.yml as it wasn't working if declared in the docker-compose.override.yml file...

[BaDos]

The internal task MCLOUD-9243 was created