Support HttpModules in event pipeline

Any HttpModules that are configured should be executed in the event pipeline of a page when testing the page

Start by locating the event pipeline used when a page is tested and the configuration path for HttpModules. Trace how configured modules are discovered and invoked, then verify that they execute as part of the page pipeline without changing existing behavior. The issue names no files or tests, so the expected execution order and test entry point need to be established first.

Written by the indexing model from the issue text.