update src/components/Dialog/src/Dialog.vue.

解决了单独使用elementplus diaolog组件时，样式被篡改的问题


Signed-off-by: AKING <2734339436@qq.com>
(cherry picked from commit cba35d698f)

src/components/Dialog/src/Dialog.vue

@@ -66,6 +66,7 @@ const dialogStyle = computed(() => {
     lock-scroll
     draggable
     top="0"
+    class="com-dialog"
     :show-close="false"
   >
     <template #header="{ close }">
@@ -106,13 +107,14 @@ const dialogStyle = computed(() => {
 </template>
 
 <style lang="scss">
-.#{$elNamespace}-overlay-dialog {
+.com-dialog {
+  .#{$elNamespace}-overlay-dialog {
     display: flex;
     justify-content: center;
     align-items: center;
-}
+  }
 
-.#{$elNamespace}-dialog {
+  .#{$elNamespace}-dialog {
     margin: 0 !important;
 
     &__header {
@@ -133,5 +135,6 @@ const dialogStyle = computed(() => {
     &__headerbtn {
       top: 0;
     }
+  }
 }
 </style>