#105721 removes web tests using the iOS simulator from the LUCI recipe. After this, the web build theoretically doesn't have a direct need for Xcode to be installed anymore. In practice, however, there are still some steps in GN that run and assume Xcode is installed. Harry's changes here (flutter/engine#32510) start to separate out some of these steps, but it may not be a complete fix. We should follow up and ensure

For now, the recipes will be changes so as to install Xcode only if we specify the Xcode version as a dependency in the .ci.yaml. Once we ensure the whole web build and unit tests can be run without Xcode, we can remove this dependency from the .ci.yaml entirely, and Xcode install will not occur during the web_engine CI check without a need to further change any of the LUCI recipes.