Should fix POS Pro custom templates not found

[thomasmery]

this might be fixed in 0.5 but I can't really test right now as I'm developing on a WC 3.0 install and don't have time to setup something proper with 2.6

and also as I needed this I thought it might be useful to 0.4 for now I can port it to 0.5 if necessary

anyways

seemed like it was not possible to add custom templates for Pos Pro Screens

this fix passes along the pos pro template dir path so it can be used as the string to be replaced when building the theme woocommerce-pos template dir path

without this fix the locate_template_file method would not replace the template dir path as it was set to the woocommerce pos template dir path and not found in the template path passed to the method

[jgangso]

While doing something similar, I think I recognized the version 0.5 comes with a new implementation of templates so I gave up, but thanks for this @thomasmery - will probably make use of it until o.5 reaches a stable state. :nerd_face: