Enable nightly build pipeline failure on docs.ms vaildation failure (Azure#35963)

Author: danieljurek

eng/pipelines/templates/stages/archetype-java-release-batch.yml

@@ -503,3 +503,5 @@ stages:
                   DocRepoLocation: $(DocRepoLocation)
                   TargetDocRepoName: ${{parameters.TargetDocRepoName}}
                   TargetDocRepoOwner: "azure-sdk"
+
+          - template: /eng/common/pipelines/templates/steps/docsms-ensure-validation.yml

eng/pipelines/templates/stages/archetype-java-release.yml

@@ -483,3 +483,5 @@ stages:
                   DocRepoLocation: $(DocRepoLocation)
                   TargetDocRepoName: ${{parameters.TargetDocRepoName}}
                   TargetDocRepoOwner: "azure-sdk"
+
+          - template: /eng/common/pipelines/templates/steps/docsms-ensure-validation.yml

eng/scripts/Language-Settings.ps1

@@ -737,6 +737,8 @@ function Get-java-DocsMsMetadataForPackage($PackageInfo) {
   }
 }
 
+# Defined in common.ps1 as:
+# $ValidateDocsMsPackagesFn = "Validate-${Language}-DocMsPackages" 
 function Validate-java-DocMsPackages ($PackageInfo, $PackageInfos, $DocValidationImageId) {
   # While eng/common/scripts/Update-DocsMsMetadata.ps1 is still passing a single packageInfo, process as a batch
   if (!$PackageInfos) {
@@ -745,9 +747,10 @@ function Validate-java-DocMsPackages ($PackageInfo, $PackageInfos, $DocValidatio
 
   if (!(ValidatePackages $PackageInfos $DocValidationImageId)) {
     Write-Error "Package validation failed" -ErrorAction Continue
+    return $false
   }
 
-  return
+  return $true
 }
 
 function Get-java-EmitterName() {