Adjusts margin to prevent overlapping elements

Naïve solution to prevent the "Click to select which tracks to keep when exporting" text from overlapping with the button to close the tracks selection menu.

src/StreamsSelector.jsx

@@ -333,7 +333,7 @@ const StreamsSelector = memo(({
 
   return (
     <>
-      <p style={{ margin: '.5em 1em' }}>{t('Click to select which tracks to keep when exporting:')}</p>
+      <p style={{ margin: '.5em 2em .5em 1em' }}>{t('Click to select which tracks to keep when exporting:')}</p>
 
       <div style={fileStyle}>
         {/* We only support editing main file metadata for now */}