Prior to this commit, when I'd create a Collection via the UI, I had a
different control element for dates. The value was an
`ActiveTriple::Relation`, which is a tell tale sign of things going
wrong. Further, the name of the HTML `input` was
`collection[date_created]` when it should've been `collection[date_created][]`.
<details><summary>Before removing partial</summary>
```
<div class="form-group optional nil_class_date_created">
<label class="string optional" for="collection_date_created">Date Created</label>
<br>
<p class="help-block">The date on which the work was created.</p>
<ul class="listing" aria-live="polite" style="padding: 0;">
<li class="field-wrapper input-group input-append">
<input value="#<ActiveTriples::Relation:0x0000ffff760e7240>" class="form-control" input_html="{:class=>"form-control", :multiple=>false}" type="date" name="collection[date_created]" id="collection_date_created">
</li>
</ul>
</div>
```
</details>
<details><summary>After removing partial</summary>
```
<div class="form-group multi_value optional collection_date_created managed"><label class="control-label multi_value optional" for="collection_date_created">Date Created</label><p class="help-block">The date on which the collection was created.</p> <ul class="listing" aria-live="polite">
<li class="field-wrapper input-group input-append">
<input class="string multi_value optional form-control collection_date_created form-control multi-text-field" name="collection[date_created][]" value="07/04/1776" id="collection_date_created" aria-labelledby="collection_date_created_label" type="text">
<span class="input-group-btn field-controls"><button type="button" class="btn btn-link remove"><span class="glyphicon glyphicon-remove"></span><span class="controls-remove-text">Remove</span> <span class="sr-only"> previous <span class="controls-field-name-text"></span></span></button></span></li>
<li class="field-wrapper input-group input-append">
<input class="string multi_value optional form-control collection_date_created form-control multi-text-field" name="collection[date_created][]" value="" aria-labelledby="collection_date_created_label" type="text">
<span class="input-group-btn field-controls"><button type="button" class="btn btn-link remove"><span class="glyphicon glyphicon-remove"></span><span class="controls-remove-text">Remove</span> <span class="sr-only"> previous <span class="controls-field-name-text"></span></span></button></span></li>
</ul><button type="button" class="btn btn-link add"><span class="glyphicon glyphicon-plus"></span><span class="controls-add-text">Add another</span></button>
</div>
```
</details>
Related to:
- https://github.com/scientist-softserv/adventist-dl/issues/620