[cDAC] Change runtime-diagnostics pipeline trigger (#117018)

* narrow scope of included files to only cDAC related files

Author: max-charlamb

eng/pipelines/runtime-diagnostics.yml

@@ -24,9 +24,9 @@ pr:
     - main
   paths:
     include:
-    - '/eng/pipelines/**'
-    - '/src/coreclr/**'
-    - '/src/native/**'
+    - eng/pipelines/**
+    - src/native/managed/cdac/**
+    - src/coreclr/debug/runtimeinfo/**
 
 extends:
   template:  /eng/pipelines/common/templates/pipeline-with-resources.yml