Remove border from file upload error state

Align the error state of the file input component to that of radios / checkboxes, where the error state is indicated by the red left-hand border on the form group and the error message.

src/govuk/components/file-upload/_index.scss

@@ -47,27 +47,4 @@
       box-shadow: inset 0 0 0 4px $govuk-input-border-colour;
     }
   }
-
-  .govuk-file-upload--error {
-    // As `upload--error` has border, it needs to have the same padding as
-    // the standard focused element.
-    margin-right: -$component-padding;
-    margin-left: -$component-padding;
-    padding-right: $component-padding;
-    padding-left: $component-padding;
-    border: $govuk-border-width-form-element-error solid $govuk-error-colour;
-
-    &:focus {
-      border-color: $govuk-input-border-colour;
-    }
-
-    // Repeat `:focus` styles to prevent error styles from being applied when
-    // input button is pressed as this moves the focus to "within".
-    // This can't be set together with `:focus` as all versions of IE fail
-    // to recognise `focus-within` and don't set any styles from the block
-    // when it's a selector.
-    &:focus-within {
-      border-color: $govuk-input-border-colour;
-    }
-  }
 }