fix(material/sort): avoid center align for sort header (#30198)

(cherry picked from commit 704dc08)

Author: andrewseguin

src/material/sort/sort-header.scss

@@ -33,7 +33,6 @@
 }
 
 .mat-sort-header-content {
-  text-align: center;
   display: flex;
   align-items: center;
 }