Make tx detail blockies 48px to match address detail page

Display consistency: blockies must be the same size everywhere.

src/popup/views/addressDetail.js

@@ -215,7 +215,7 @@ function copyableHtml(text, extraClass) {
 
 function blockieHtml(address) {
     const src = makeBlockie(address);
-    return `<img src="${src}" width="16" height="16" style="image-rendering:pixelated;border-radius:50%;margin-right:4px;vertical-align:middle;flex-shrink:0;display:inline-block">`;
+    return `<img src="${src}" width="48" height="48" style="image-rendering:pixelated;border-radius:50%;display:inline-block">`;
 }
 
 function txDetailAddressHtml(address) {