Remove system module from kernel tests that don't need it

Problem/Motivation

Follow-up to #2943436: Review all tests where system module is the only dependency

Steps to reproduce

Proposed resolution

Use this bash script to find and replace possible candidates. If the test fails it will be reverted. If it passes, we can review and commit the change.

find core/ -type f -name '*Test.php' \
  | grep -E '/Kernel(/|Tests/)' \
  | while read -r FILE; do
    if grep -q "^    'system',\$" "$FILE"; then
      sed -i "/^    'system',\$/d" "$FILE"

      if ! ./vendor/bin/phpunit --stop-on-error --stop-on-fail -c core/phpunit.xml.dist "$FILE"; then
        echo "Test failed for $FILE, reverting..."
        git checkout -- "$FILE"
      else
        echo "Test passed for $FILE"
      fi
    fi
  done

Remaining tasks

Repeat for other modules

User interface changes

N/A

Introduced terminology

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

N/A