PLT-5000 (#4817) Fix file upload alignment in tablet and mobile view (#4826)

webapp/sass/responsive/_mobile.scss

@@ -1075,7 +1075,7 @@
             }
 
             .post-create-footer {
-                padding: 1em 0;
+                padding: 0 45px 0 45px;
 
                 .control-label {
                     margin: .5em 0;

webapp/sass/responsive/_tablet.scss

@@ -26,7 +26,7 @@
         }
 
         .post-create-footer {
-            padding: 0 1em;
+            padding: 0 45px 0 45px;
 
             .msg-typing {
                 display: none;