refactor: remove soap extension as it's shipped in image

Signed-off-by: Bart Jaskulski <bjaskulski@protonmail.com>

includes/metrics.yml

@@ -6,9 +6,6 @@
   allow_failure: true
   needs:
     - prepare prefixed vendor
-  before_script:
-    - apt-get update -yq && apt-get install -yq --no-install-recommends libxml2-dev
-    - docker-php-ext-install soap
 
 phpmetric metrics:
   <<: *job-metrics