Fix markdown card image sizing (#28449)

src/components/ha-assist-chat.ts

@@ -134,6 +134,7 @@ export class HaAssistChat extends LitElement {
               })}"
               breaks
               cache
+              assist
               .content=${message.text}
             >
             </ha-markdown>

src/components/ha-markdown.ts

@@ -70,13 +70,15 @@ export class HaMarkdown extends LitElement {
     a {
       color: var(--markdown-link-color, var(--primary-color));
     }
+    :host([assist]) img {
+      height: auto;
+      width: auto;
+      transition: height 0.2s ease-in-out;
+    }
     img {
       background-color: var(--markdown-image-background-color);
       border-radius: var(--markdown-image-border-radius);
       max-width: 100%;
-      height: auto;
-      width: auto;
-      transition: height 0.2s ease-in-out;
     }
     p:first-child > img:first-child {
       vertical-align: top;