7/2025: delete obsolete data from `openapi-platform / openapiPipeline / PipelineResults` Cosmos DB collection to prevent it from reaching the limit.

This is a follow-up to:

- https://github.com/Azure/azure-sdk-tools/issues/8389

For context see here:

- https://github.com/Azure/azure-sdk-tools/issues/8389#issuecomment-2201368335

Start with gathering metrics how fast the data grew as done here:

- https://github.com/Azure/azure-sdk-tools/issues/8389#issuecomment-2153483392

Then start deleting and measuring progress as seen here:

- https://github.com/Azure/azure-sdk-tools/issues/8389#issuecomment-2183553922

But start by providing one-time link to the queries as seen here:

- https://github.com/Azure/azure-sdk-tools/issues/8389#issuecomment-2153505213

Finally, set up follow-up email as explained here:

- https://github.com/Azure/azure-sdk-tools/issues/8389#issuecomment-2201368335