Fix plugin reload (#14409)
Fixes #14408
Summary of the issue:
PR #14350 streamlined import code for globalPlugins and appModules. However, the reloading of these modules was overlooked.
Description of user facing changes
Reloading of appModules/globalPlugins works again
Description of development approach
The reloading functions for both appModules and globalPlugins call addonhandler.packaging.addDirsToPythonPackagePath
