BLD: Unbreak github tests workflow

missing parenthesis introduced in matplotlib#25145 

Reformatted the if block based on a similar set of conditions from the cygwin tests to make it more readable and help locate the error.

I will exercise the unbreak CI self merge upon green CI (unless objected to)

Author: ksunden

.github/workflows/tests.yml

@@ -25,7 +25,15 @@ env:
 
 jobs:
   test:
-    if: "github.event_name == 'workflow_dispatch' || github.repository == 'matplotlib/matplotlib' && !contains(github.event.head_commit.message, '[ci skip]') && !contains(github.event.head_commit.message, '[skip ci]') && !contains(github.event.head_commit.message, '[skip github]' && !contains(github.event.head_commit.message, '[ci doc]')"
+    if: |
+      github.event_name == 'workflow_dispatch' ||
+      (
+        github.repository == 'matplotlib/matplotlib' &&
+        !contains(github.event.head_commit.message, '[ci skip]') &&
+        !contains(github.event.head_commit.message, '[skip ci]') &&
+        !contains(github.event.head_commit.message, '[skip github]') &&
+        !contains(github.event.head_commit.message, '[ci doc]')
+      )
     permissions:
       contents: read
     name: "Python ${{ matrix.python-version }} on ${{ matrix.os }} ${{ matrix.name-suffix }}"