title: Material ui - snackbox aria label not being read
body: <p>So I have several components all with aria labels or aria labelled by tags attached to them for users with screenreaders. </p>
  
  <p>No matter what I try, I can't get the aria label to work on material ui snack boxes. I'm currently using NVDA screen reader as that is our company default. </p>
  
  <p>Does anyone know a solution, or have had the same problem with this?</p>
  
  <p>Example code: (Note that the aria label for the close button works fine!) </p>
  
  <pre><code> &lt;Snackbar
          classname='warningSnack'
          anchorOrigin={{
             vertical: 'bottom',
             horizontal: 'left',
          }}
          open={snackOpen}
          autoHideDuration={8000}
          onClose={handleClose}
          aria-label = {"Please read this"}
         // ContentProps={{
         //   'aria-describedby': 'please read me',
         // }} WONT WORK
          message={'this is my message'}
          action={[
            &lt;IconButton
              key="close"
              aria-label="close"
              color="inherit"
              className={close}
              onClick={handleClose}
            &gt;
              &lt;CloseIcon /&gt;
            &lt;/IconButton&gt;,
          ]}
        /&gt;
  </code></pre>