fix(picker): use correct spacing between icons and label text

The spacing between alert icon and disclosure icon was incorrect
because it was being overridden by a selector that shouldn't have been
affecting this scenario. The selector was matching because it was using
the subsequent-sibling combinator (~) instead of the next-sibling
combinator (+) -- that CSS was meant only for the case of the spacing
between label text and disclosure icon, when there is no invalid icon
or progress circle.

Author: jawinn

components/picker/index.css

@@ -343,12 +343,13 @@ governing permissions and limitations under the License.
   &.is-loading,
   &.is-invalid {
     .spectrum-Picker-label {
+      /* Spacing after label text when there is an invalid icon or progress circle. */
       margin-inline-end: var(--mod-picker-spacing-text-to-icon-inline-end, var(--spectrum-picker-spacing-text-to-icon-inline-end));
     }
   }
 }
 
-/* Optional icon that appears before the text within the picker. */
+/* Optional workflow icon that appears before the text within the picker. */
 .spectrum-Picker .spectrum-Picker-icon {
   flex-shrink: 0;
   margin-inline-end: var(--mod-picker-spacing-text-to-icon, var(--spectrum-picker-spacing-text-to-icon));
@@ -435,7 +436,8 @@ governing permissions and limitations under the License.
   margin-block-end: calc(var(--mod-picker-spacing-top-to-progress-circle, var(--spectrum-picker-spacing-top-to-progress-circle)) - var(--mod-picker-border-width, var(--spectrum-picker-border-width)));
 }
 
-.spectrum-Picker-label ~ .spectrum-Picker-menuIcon {
+.spectrum-Picker-label + .spectrum-Picker-menuIcon {
+  /* Spacing after label text when there is no invalid icon or progress circle (to disclosure icon). */
   margin-inline-start: var(--mod-picker-spacing-text-to-icon, var(--spectrum-picker-spacing-text-to-icon));
 }