[typespec-ci] Add pr trigger for eng/tools/TypeSpecValidation (Azure#24640)

Author: mikeharder

eng/pipelines/typespec-ci.yml

@@ -15,6 +15,7 @@ pr:
     - package-lock.json
     - eng/pipelines/typespec-ci.yml
     - eng/pipelines/templates/steps/typespec-ci.yml
+    - eng/tools/TypeSpecValidation
     - specification/contosowidgetmanager
     - specification/cognitiveservices
     - specification/confidentialledger