Summary
What is the problem or use case, what are we trying to achieve?

Fix the build command for the temporary S3 evergreen build. The S3 extension is currently not compiling on evergreen as the build command has not been updated to reflect the new CMake flag added in WT-8705.

Suggested Solution
Is there any suggested solution to handle this issue? Is it related to any existing WT ticket? Is it related to any previous issue fixed? If yes, link the WT ticket number using related to, depends on, dependent on by links

Update the evergreen.yml with the new CMake flag to specify to build the extension as an external project.