refactor(export): remove redundant header select-all text action

src/pages/ExportPage.scss

@@ -1199,7 +1199,6 @@
     }
   }
 
-  .selection-toggle-btn,
   .selection-clear-btn {
     border: 1px solid var(--border-color);
     border-radius: 8px;
@@ -1220,13 +1219,6 @@
     }
   }
 
-  .selection-toggle-btn {
-    padding: 4px 8px;
-    font-size: 11px;
-    line-height: 1.2;
-    white-space: nowrap;
-  }
-
   .selection-export-btn {
     border: none;
     border-radius: 8px;
@@ -2705,11 +2697,6 @@
     gap: 6px;
   }
 
-  .table-wrap .selection-toggle-btn {
-    padding: 3px 7px;
-    font-size: 10px;
-  }
-
   .table-wrap .contacts-list-header-actions {
     gap: 6px;
   }

src/pages/ExportPage.tsx

@@ -4174,14 +4174,6 @@ function ExportPage() {
                     </button>
                   </span>
                   <span className="contacts-list-header-main">
-                    <button
-                      className="selection-toggle-btn"
-                      type="button"
-                      onClick={toggleSelectAllVisible}
-                      disabled={visibleSelectableCount === 0}
-                    >
-                      {isAllVisibleSelected ? '取消全选当前筛选' : '全选当前筛选'}
-                    </button>
                     <span className="contacts-list-header-main-label">联系人（头像/名称/微信号）</span>
                   </span>
                   <span className="contacts-list-header-count">总消息数</span>