Fix metadata viewer layout with overflow

Author: axelboc

apps/demo/src/h5wasm/DropZone.module.css

@@ -38,6 +38,7 @@
 .h5web {
   flex: 1;
   display: flex;
+  min-width: 0;
   height: 100vh;
   z-index: 0; /* STACKING CONTEXT */
 }

packages/app/src/metadata-viewer/MetadataViewer.module.css

@@ -48,6 +48,7 @@
 }
 
 .metadataViewer {
+  flex: 1;
   overflow-y: scroll;
   scrollbar-width: thin;
 }