title: ag-grid filter issue with valueGetter and renderer
body: <p>I am trying to create a hyperlink from the data coming as string or array like {"value":["link text~docid","link text1~docid1"]}. I am creating link(s) using cell renderer. But then filter for this column shows "link text~docid". Where as I want it to display only "link text". 
  Issue is when I use valueGetter, it modifies the "params.data.value to {"value":["link text","link text1"]} so I can't generate my hyperlink.
  I want to check if there is any way in ag-grid to calculate value but keep the params.data intact so that it can be used in cellRenderer?</p>
  
  <p><strong>Example Data</strong></p>
  
  <pre><code>{ "Stream": ["AA Stream (Live) (V2)~LPFC-A7ECNL"], "status": "Approved", "level": "Primary", "title": "adam resource- name change", "Phase": ["adam test phase~UKAT-A6HF9Q"], "id": 0, "Substage": null, "Stage": ["Ga stage 1~UKAT-A7GET3"], "Activity": "11 a~LPFC-A7TC4J" }
  </code></pre>