fix(file-uploader): do not render empty element if labelTitle, labelDescription not provided

Fixes #1775

src/FileUploader/FileUploader.svelte

@@ -103,18 +103,22 @@
   on:mouseenter
   on:mouseleave
 >
+  {#if labelTitle}
     <p
       class:bx--file--label="{true}"
       class:bx--label-description--disabled="{disabled}"
     >
       {labelTitle}
     </p>
+  {/if}
+  {#if labelDescription}
     <p
       class:bx--label-description="{true}"
       class:bx--label-description--disabled="{disabled}"
     >
       {labelDescription}
     </p>
+  {/if}
   <FileUploaderButton
     disabled="{disabled}"
     disableLabelChanges