Tweak css workaround to apply only to image browser tab

Add id selector for image browser tab so the css rule doesn't crop thumbnails in other tabs (e.g. txt2img results pane)

style.css

@@ -17,7 +17,7 @@ div[id^="image_browser_tab"][id$="image_browser_gallery"].hide_loading > .svelte
 /* Workaround until gradio version is updated to a version that fixes it
    see https://github.com/gradio-app/gradio/issues/1590
 */
-.thumbnail-item > img {
+#tab_image_browser .thumbnail-item > img {
   width: auto !important;
   height: auto !important;
 }