ui-plugin-find-eresource should use values not labels when apply filters

Overview:
ui-plugin-find-eresource should use values not labels when apply filters (as labels can be changed)

Steps to Reproduce:

1. Go to the Agreements app, select "E-resources" tab in left hand panel
2. Click action menu (top right of results pane) and select "Move identifiers"
3. Click one of the "select title" buttons to get the eresource find plugin search and filter
4. Open the developer console network tab in browser
5. Click one of the options in the filter "Monograph" or "Serial"
6. Inspect the network call made - see that we have a URL including parameter filters=type.label%3D%3DMonograph or filters=type.label%3D%3DSerial

Expected Results:
It should be using type.value and monograph/serial (or other values) instead of the label