content: display N/A in search results if package does not have a license
Fixes b/135141704
<b class="SearchSnippet-subtextTitle">Version:</b> {{.Version}}
<span class="SearchSnippet-subtextDivide">|</span>
<b class="SearchSnippet-subtextTitle">{{pluralize (len .Licenses) "License"}}:</b>
+ {{if .Licenses}}
{{range $i, $e := .Licenses -}}{{if $i}}, {{end}} {{$e}} {{end}}
+ {{else}}
+ <span>N/A</span>
+ {{end}}
</div>
<div class="SearchSnippet-subtext">
<b class="SearchSnippet-subtextTitle">Imported by:</b> {{.NumImportedBy}}
