fix(editor): improve pdf embed viewer UX (#11641)

Closes: [BS-3101](https://linear.app/affine-design/issue/BS-3101/pdf-embed-模式的选中框选-和点开看详情有比较大的问题)

### What's Changed!

* Fixed disable pointer event in native pdf viewer by dragging
* Disable opening peek view with pdf viewer in readonly and sharing modes

packages/frontend/core/src/blocksuite/block-suite-editor/lit-adaper.tsx

@@ -155,7 +155,9 @@ const usePatchSpecs = (mode: DocMode) => {
   );
 
   const enablePDFEmbedPreview = useLiveData(
-    featureFlagService.flags.enable_pdf_embed_preview.$
+    featureFlagService.flags.enable_pdf_embed_preview.$.map(
+      flag => !workspaceService.workspace.openOptions.isSharedMode && flag
+    )
   );
 
   const patchedSpecs = useMemo(() => {