1ES pipeline schema feature assumes that all pipeline files extend 1ES pipeline templates

[lbussell]

Hello, I tried out the 1ES pipeline template feature in this extension. We have a relatively complex pipeline. The pipeline goes through a couple levels of indirection before reaching the 1ES pipeline template itself. Additionally, we use dozens of different templates throughout the pipeline.

When I set "azure-pipelines.1ESPipelineTemplatesSchemaFile": true, the extension assumes that every file is a standalone pipeline. Obviously that's not always the case when you're using lots of templates.

Here's one of our pipeline definitions, for example:
https://github.com/dotnet/docker-tools/blob/main/eng/pipelines/dotnet-buildtools-image-builder-official.yml