Update inspector view design

Due to a11y visual issue, update inspector page toolbar design
and also update elevation to fit design mock.

Bug: 123209419
Test: manual
Test: atest DocumentsUIGoogleTests
Change-Id: I784af24dc17862a3d1621d17b612443627248c4c
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 9ab36a1..6d9f7b3 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -81,7 +81,7 @@
     <dimen name="bottom_bar_button_horizontal_padding">24dp</dimen>
     <dimen name="bottom_bar_button_corner_radius">4dp</dimen>
 
-    <dimen name="inspector_header_height">350dp</dimen>
+    <dimen name="inspector_header_height">280dp</dimen>
 
     <dimen name="root_info_header_height">60dp</dimen>
     <dimen name="root_info_header_horizontal_padding">24dp</dimen>