Use separate workflows

Signed-off-by: Alex Le <alex.le@improving.com>

Author: Aryex

.github/workflows/check-code-examples.yml

@@ -1,8 +1,8 @@
 name: Check C# Examples
 
 on:
-  workflow_call:
-  workflow_dispatch:
+  pull_request:
+    branches: [main]
 
 permissions:
   contents: read

.github/workflows/check-csharp-examples.yml

@@ -5,7 +5,8 @@ name: Check Node Examples
 # See scripts/validators/node.py.
 
 on:
-  workflow_call:
+  pull_request:
+    branches: [main]
   workflow_dispatch:
 
 permissions: