Update submodules in PR template test job (#62487)

Author: wtgodbe

.azure/pipelines/template-tests-pr.yml

@@ -33,6 +33,8 @@ jobs:
     agentOs: Windows
     timeoutInMinutes: 180
     steps:
+    - script: git submodule update --init
+      displayName: Update submodules
     # Build the shared framework
     - script: ./eng/build.cmd -ci -prepareMachine -nativeToolsOnMachine -nobl -all -pack -arch x64
               /p:CrossgenOutput=false /p:ASPNETCORE_TEST_LOG_DIR=artifacts/log /p:VsTestUseMSBuildOutput=false