Fix Signature Request styles (#15621)

* SignatureRequestOriginal: fix collapsing ui

* SignatureRequestOrigin: fix collapsing icon

ui/components/app/signature-request-original/index.scss

@@ -153,7 +153,6 @@
     display: flex;
     flex-flow: column;
     flex: 1 1 auto;
-    height: 0;
   }
 
   &__origin-row {
@@ -168,6 +167,10 @@
     margin-right: 5px;
   }
 
+  &__origin-icon {
+    flex: 0 0 24px;
+  }
+
   &__origin {
     margin-left: 5px;
   }
@@ -193,7 +196,7 @@
 
   &__rows {
     height: 100%;
-    overflow-y: scroll;
+    overflow-y: auto;
     overflow-x: hidden;
     border-top: 1px solid var(--color-border-default);
     display: flex;

ui/components/app/signature-request-original/signature-request-original.component.js

@@ -141,6 +141,7 @@ export default class SignatureRequestOriginal extends Component {
         </div>
         {targetSubjectMetadata?.iconUrl ? (
           <SiteIcon
+            className="request-signature__origin-icon"
             icon={targetSubjectMetadata.iconUrl}
             name={
               getURLHostName(targetSubjectMetadata.origin) ||