p13n: keep tab elements in one line

The elements within the tab container should remain in the same line
when the screen width changes.
Before: http://go/scrcast/NTc4Mjc0MDEzNjg4NjI3MnxmZTE1MDQyNS1kZA
After: http://go/scrcast/NTg5NDA5MzQ3MjI2ODI4OHxkMzgxNGVlMC0wMw

Bug: 397957114
Test: Manually
Change-Id: Ib3291f47c679f786a89a29f058f3b36f6d320d0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6333946
Reviewed-by: Jason Thai <jasontt@chromium.org>
Commit-Queue: Thuong Phan <thuongphan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1429664}

ash/webui/common/resources/sea_pen/sea_pen_freeform_element.html

@@ -46,6 +46,12 @@
     background-color: var(--cros-sys-hover_on_subtle);
   }
 
+  #tabContainer {
+    display: flex;
+    flex-shrink: 0;
+    flex-wrap: nowrap;
+  }
+
   #tabContainer,
   #promptingGuide {
     flex-grow: 1;
@@ -60,6 +66,7 @@
     font: var(--cros-annotation-1-font);
     margin-top: 16px;
     padding-inline-end: 0;
+    padding-inline-start: 16px;
   }
 
   #shuffle {