fix: remove duplicate Catalog breadcrumb on asset detail pages (#21820)

I think it's easiest to see these two fixes in a quick demo:
https://www.loom.com/share/ecec7b76aad44dd78115ac3d79a64ec0

- The assetOverviewBreadcrumbs array included an explicit {text:
'Catalog'} item followed by the ViewBreadcrumb component, which itself
renders "Catalog / [view name]". This caused the breadcrumb trail to
read "Catalog > Catalog / All Assets" instead of just "Catalog / All
Assets".

- The vertical positioning of the breadcrumbs moved as you moved from
page to page

---------

Co-authored-by: Claude <noreply@anthropic.com>
Internal-RevId: 72e502e69554cb10daf90bfe8b8bd1715a2b8dc6

Author: 2 people

js_modules/ui-core/src/assets/catalog/AssetsCatalog.tsx

@@ -24,10 +24,9 @@ export const AssetsCatalog = React.memo(() => {
       }}
     >
       <Box
-        padding={{top: 12, horizontal: 24}}
+        padding={{top: 8, horizontal: 24}}
         flex={{direction: 'row', alignItems: 'center', justifyContent: 'space-between'}}
-        border="top"
-        style={{width: '100%'}}
+        style={{width: '100%', minHeight: 44, marginBottom: -4}}
       >
         <ViewBreadcrumb />
       </Box>

js_modules/ui-core/src/shared/assets/AssetPageHeader.tsx

@@ -102,12 +102,19 @@ export const AssetPageHeader = ({
                 // items have the correct href values since we can't control the overflow
                 // rendering. Here, however, we can do what we want, and we render with
                 // react-router Link components that don't need the basePath.
-                const pathWithoutBase = href ? href.replace(basePath, '') : '';
+                if (href) {
+                  return (
+                    <TruncatedHeading key={href}>
+                      <BreadcrumbLink to={href.replace(basePath, '') || '#'}>
+                        {typeof text === 'string' ? <MiddleTruncate text={text} /> : text}
+                      </BreadcrumbLink>
+                    </TruncatedHeading>
+                  );
+                }
+
                 return (
                   <TruncatedHeading key={href}>
-                    <BreadcrumbLink to={pathWithoutBase || '#'}>
-                      {typeof text === 'string' ? <MiddleTruncate text={text} /> : text}
-                    </BreadcrumbLink>
+                    {typeof text === 'string' ? <MiddleTruncate text={text} /> : text}
                   </TruncatedHeading>
                 );
               }}