fix: don't display buy new stamp button when already in process of buying one (#422)

src/pages/files/UploadActionBar.tsx

@@ -67,6 +67,7 @@ export function UploadActionBar({
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           </SwarmButton>
         </ExpandableListItemActions>
+        {hasAnyStamps && (
           <SwarmButton
             disabled={stampMode === 'BUY' && !hasAnyStamps}
             onClick={() => setStampMode(stampMode === 'BUY' ? 'SELECT' : 'BUY')}
@@ -74,6 +75,7 @@ export function UploadActionBar({
           >
             {stampMode === 'BUY' ? 'Use Existing Stamp' : 'Buy New Stamp'}
           </SwarmButton>
+        )}
       </Grid>
     )
   }