Multi-trace traceID search does not show 404s

[black-adder]

Cf. https://github.com/uber/jaeger/issues/310

When a user retrieves multiple traces, a single trace that doesn't exist (due to TTLing) will return an error for the entire batch. This has been fixed on the query side to return as many traces as possible + errors for the traces that couldn't be fetched.

Current version of the UI does not parse the errors portion of the response, it only seems to react to the status code.

[tiffon]

Something along these lines should work:

The markup for the error list item:

<div class="ResultItem" style="
    border: 1px solid #fbb;
"><div class="ResultItem--title clearfix" style="
    background: hsla(0, 100%, 96%, 1);
    border: none;
"><h3 class="ub-m0 ub-relative" style="
    color: #c00;
                                     "><span style="
    /* color: rgba(0,0,0,0.75); */
">Trace not found:</span><span style="
    color: rgba(0,0,0,0.75);
"> dad19e3d79b8af</span></h3></div></div>

(Needs to be cleaned up, etc.)