Nodes without a URL still hyperlink the source field

[dhimmel]

From https://het.io/search/?source=26663&target=14379

For the "source" field of the target node, the hyperlink for "Reactome via Pathway Commons" is empty:

<div class="info_table_value small left"><div tabindex="0" class="dynamic_field " data-expanded="false"><a class="nowrap" href="">Reactome via Pathway Commons</a></div></div>

This is because the API does not return a URL:

{
    "id": 14379,
    "identifier": "PC7_6055",
    "identifier_type": "str",
    "name": "Orexin and neuropeptides FF and QRFP bind to their respective receptors",
    "properties": {
        "source": "Reactome via Pathway Commons",
        "license": "CC BY 4.0"
    },
    "metanode": "Pathway"
}

I'm thinking in these cases we should just not show any hyperlink rather than a blank one (which in my browser ends up going to the current address).

[vincerubinetti]

Sorry, didn't realize you had reported this several months before Casey mentioned it to me! This was closed with #163