[Serverless]: Explain what lightweight tests vs. monitoring browser tests are in Synthetics pricing

[ppf2]

Serverless Docs

Elastic Observability

Description

Some users need help understanding what lightweight tests vs. monitoring browser tests are on this pricing page:

https://www.elastic.co/pricing/serverless-observability

It will be helpful to cross link to product documentation explaining these features, e.g.

https://www.elastic.co/guide/en/serverless/current/observability-synthetics-lightweight.html
https://www.elastic.co/guide/en/serverless/current/observability-synthetics-journeys.html

Resources and additional context

https://www.elastic.co/pricing/serverless-observability