ci(solr): skip update-fields.sh test for no input if on Github IQSS#7903

Inside update-fields.sh we detect if a STDIN is given as a pipe via
testing if FD 0 (stdin) is not attached to a terminal.
This does not work inside a Github Action, so skip this for now till
we see a problem or find a better solution.

tests/shell/spec/update_fields_spec.sh

@@ -76,7 +76,11 @@ Describe "Update fields command"
 
   Describe "reading input"
     Describe "fails because"
+      # Test if $CI is set (always true inside Github Workflow)
+      detect_github_action() { test -z ${CI:+x}; }
+
       It "throws error when no source given"
+        Skip if "running on Github Action" detect_github_action
         When run update_fields data/solr/minimal-schema.xml
         The status should equal 2
         The error should include "provide source file or piped input"