Modify font weight for AssistantTextElementView.

Change made in response to spec clarification by UX.

Bug: b:78138093
Change-Id: Ie4b642d593f51051ea3f116f73954283e8475345
Reviewed-on: https://chromium-review.googlesource.com/1129553
Commit-Queue: David Black <dmblack@google.com>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573471}

ash/assistant/ui/main_stage/assistant_text_element_view.cc

@@ -17,7 +17,9 @@ AssistantTextElementView::AssistantTextElementView(
     : views::Label(base::UTF8ToUTF16(text_element->text())) {
   SetAutoColorReadabilityEnabled(false);
   SetEnabledColor(kTextColorPrimary);
-  SetFontList(views::Label::GetDefaultFontList().DeriveWithSizeDelta(2));
+  SetFontList(views::Label::GetDefaultFontList()
+                  .DeriveWithSizeDelta(2)
+                  .DeriveWithWeight(gfx::Font::Weight::MEDIUM));
   SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_LEFT);
   SetMultiLine(true);
 }