fix(material/list): use flexbox to size mat-line elements (#19809) (#19819)

Use `flex: auto` instead of `width: 100%` to size `.mat-list-text` elements. using `width: 100%` can lead to `.mat-list-text` sibling elements shrinking and having their content overflow.

Author: swseverance

src/material/core/style/_list-common.scss

@@ -37,7 +37,7 @@
 
   display: flex;
   flex-direction: column;
-  width: 100%;
+  flex: auto;
   box-sizing: border-box;
   overflow: hidden;