Remove recursion from unit test scenarios (#5277)

## What are you changing in this pull request and why?

Recursion is not currently working for BigQuery
(dbt-labs/dbt-bigquery#1178), so per
@graciegoheen, remove this from the scenarios until it is resolved.

## Checklist
- [x] Review the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.

website/docs/docs/build/unit-tests.md

@@ -37,7 +37,6 @@ You should unit test a model:
     - Window functions
     - `case when` statements when there are many `when`s
     - Truncation
-    - Recursion
 - When you're writing custom logic to process input data, similar to creating a function.
 - We don't recommend conducting unit testing for functions like `min()` since these functions are tested extensively by the warehouse. If an unexpected issue arises, it's more likely a result of issues in the underlying data rather than the function itself. Therefore, fixture data in the unit test won't provide valuable information.
 - Logic for which you had bugs reported before.
@@ -287,4 +286,4 @@ There is currently no way to unit test whether the dbt framework inserted/merged
 - [Unit testing versioned models](/reference/resource-properties/unit-testing-versions)
 - [Unit test inputs](/reference/resource-properties/unit-test-input)
 - [Unit test overrides](/reference/resource-properties/unit-test-overrides)
-- [Platform-specific data types](/reference/resource-properties/data-types)
+- [Platform-specific data types](/reference/resource-properties/data-types)