Add RUM Sample Rate Audit

There have been cases where the RUM sample rate was set to e.g. 1 instead of the recommended 100. Context: https://adobe-dx-support.slack.com/archives/C050M6XFWCF/p1713347373771179

@trieloff @kptdobe anything to add as to the value of this audit?

No source file, test, or entry point is named. Start by reviewing the existing audit-worker structure and the Slack context to define the expected RUM sample-rate audit; done should include detecting values such as 1 when the recommended value is 100 and documenting the expected audit result.

Written by the indexing model from the issue text.