make graph fill only visiable space on the page

Signed-off-by: Maximilian Vorbrodt <maximilian.vorbrodt@hotmail.com>

packages/core-components/src/components/DependencyGraph/DependencyGraph.tsx

@@ -223,6 +223,7 @@ export function DependencyGraph<NodeData, EdgeData>(
 
   const maxWidth = Math.max(graphWidth, containerWidth);
   const maxHeight = Math.max(graphHeight, containerHeight);
+  const minHeight = Math.min(graphHeight, containerHeight);
 
   const containerRef = React.useMemo(
     () =>
@@ -393,7 +394,8 @@ export function DependencyGraph<NodeData, EdgeData>(
     <svg
       ref={containerRef}
       {...svgProps}
-      width="100%"
+      width='100%'
+      height={minHeight}
       viewBox={`0 0 ${maxWidth} ${maxHeight}`}
     >
       <defs>

plugins/explore/src/components/GroupsExplorerContent/GroupsDiagram.tsx

@@ -44,7 +44,7 @@ import useAsync from 'react-use/lib/useAsync';
 const useStyles = makeStyles((theme: BackstageTheme) => ({
   graph: {
     flex: 1,
-    minHeight: 0,
+    minHeight: '100%',
   },
   graphWrapper: {
     position: 'relative',