fix(list): incorrect item spacing with trailing meta in RTL

Currently if developers use the `mdc-list-item` in RTL mode with
`--with-trailing-meta`, `--with-trailing-icon` et all, the horizontal
spacing on the start breaks due to the `reflexive-property` incorrectly
using `auto` instead of the default `16px` for the start side. The `auto`
value accidentally overrides the already-set `16px` horizontal padding
resulting in no side padding at the start.

Fixes #7024.

Author: devversion

packages/mdc-list/_evolution-mixins.scss

@@ -696,8 +696,7 @@
   @include feature-targeting.targets($feat-structure) {
     // Extra specificity needed to override default customizations.
     &.mdc-list-item {
-      // We rely on auto to avoid clobbering the opposite padding.
-      @include rtl-mixins.reflexive-property(padding, 0, auto);
+      @include rtl-mixins.reflexive-property(padding, 0, 16px);
     }
 
     .mdc-list-item__start {
@@ -715,8 +714,7 @@
   @include feature-targeting.targets($feat-structure) {
     // Extra specificity needed to override default customizations.
     &.mdc-list-item {
-      // We rely on auto to avoid clobbering the opposite padding.
-      @include rtl-mixins.reflexive-property(padding, auto, 0);
+      @include rtl-mixins.reflexive-property(padding, 16px, 0);
     }
 
     .mdc-list-item__end {