hook_modules_installed() accepts a list of modules and runs after they have all been installed. This means that we have no way to react after each module has been installed. This causes differences when mutliple modules are enabled at the same time vs single modules being enabled. We should change it to
hook_module_installed() and fire it as part of the final part of the install loop for each module.
This would mean that the current code in
field_modules_installed() once move would negate the need for