test.yml: use a constant list instead of fromJSON

This was pointed out by zizmor, the GHA linter.

Author: nicoddemus

.github/workflows/test.yml

@@ -240,25 +240,7 @@ jobs:
             tox_env: "doctesting"
             use_coverage: true
 
-    continue-on-error: >-
-      ${{
-        contains(
-          fromJSON(
-            '[
-              "windows-py310-pluggy",
-              "windows-py313",
-              "ubuntu-py310-pluggy",
-              "ubuntu-py310-freeze",
-              "ubuntu-py313",
-              "macos-py310",
-              "macos-py313"
-            ]'
-          ),
-          matrix.name
-        )
-        && true
-        || false
-      }}
+    continue-on-error: ${{ contains(['windows-py310-pluggy','windows-py313','ubuntu-py310-pluggy','ubuntu-py310-freeze','ubuntu-py313','macos-py310','macos-py313'], matrix.name ) && true || false }}
 
     steps:
     - uses: actions/checkout@v5