[ci] Fix variable names for release triggering build (dotnet#6887)

Context: https://docs.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/resources-pipelines-pipeline?view=azure-pipelines#the-pipeline-resource-metadata-as-predefined-variables

Commit 7982895 added a new pipeline that can be used to trigger release
definitions, however the automatic trigger was not fully testable until
after it was merged.

Update the new pipeline to use the correct variable names that are set
when it is automatically triggered by the Xamarin.Android pipeline.

build-tools/automation/azure-pipelines-release-trigger.yaml

@@ -23,18 +23,22 @@ jobs:
   steps:
   - checkout: none
 
+  - powershell: 'gci env: | format-table -autosize -wrap'
+    displayName: print environment variables
+
   - powershell: |
       $triggeringBuild = @{
           "triggeringBuild" = @{
-              "id" = "$(Build.TriggeredBy.BuildId)"
-              "pipeline" = "$(Build.TriggeredBy.DefinitionId)"
-              "project" = "$(Build.TriggeredBy.ProjectID)"
+              "id" = "$(resources.pipeline.xamarin-android.runID)"
+              "pipeline" = "$(resources.pipeline.xamarin-android.pipelineID)"
+              "branch" = "$(resources.pipeline.xamarin-android.sourceBranch)"
+              "commit" = "$(resources.pipeline.xamarin-android.sourceCommit)"
           }
       }
       $json = $triggeringBuild | ConvertTo-Json
       New-Item -Path $(Build.StagingDirectory) -Name triggering-build.json -ItemType file -Value $json -Force
       $jsonContent = Get-Content "$(Build.StagingDirectory)\triggering-build.json" | ConvertFrom-Json
-      Write-Host Triggering Build Info: $jsonContent.triggeringBuild.project - $jsonContent.triggeringBuild.pipeline - $jsonContent.triggeringBuild.id
+      Write-Host Triggering Pipeline and Run IDs: $jsonContent.triggeringBuild.pipeline - $jsonContent.triggeringBuild.id
     displayName: write triggering-build.json
 
   - task: PublishPipelineArtifact@1