experimental: Video uploads fixes accept support (#5153)

## Description

Now Video elelment shows only video files. 

<img width="1016" alt="image"
src="https://github.com/user-attachments/assets/0c846430-1e6d-4acd-8a1a-aa0111d39292"
/>


## Steps for reproduction

1. click button
2. expect xyz

## Code Review

- [ ] hi @kof, I need you to do
  - conceptual review (architecture, feature-correctness)
  - detailed review (read every line)
  - test it on preview

## Before requesting a review

- [ ] made a self-review
- [ ] added inline comments where things may be not obvious (the "why",
not "what")

## Before merging

- [ ] tested locally and on preview environment (preview dev login:
0000)
- [ ] updated [test
cases](https://github.com/webstudio-is/webstudio/blob/main/apps/builder/docs/test-cases.md)
document
- [ ] added tests
- [ ] if any new env variables are added, added them to `.env` file

Author: istarkov

apps/builder/app/builder/shared/assets/asset-upload.tsx

@@ -71,7 +71,7 @@ export const acceptUploadType = (
   file: File
 ) => {
   if (accept !== undefined) {
-    acceptFileTypeSpecifier(accept, file);
+    return acceptFileTypeSpecifier(accept, file);
   }
 
   return acceptFileTypeSpecifier(acceptMap[assetType], file);

apps/builder/app/builder/shared/image-manager/image-manager.tsx

@@ -55,11 +55,19 @@ const useLogic = ({
   const filteredItems = useMemo(() => {
     let acceptable = assetContainers;
     const patterns = acceptToMimePatterns(accept ?? "");
+
     if (patterns !== "*") {
       acceptable = assetContainers.filter((item) =>
         doesAssetMatchMimePatterns(item.asset, patterns)
       );
+    } else if (accept !== undefined) {
+      // Filter by file extension
+      const extensions = accept.split(",").map((ext) => ext.trim());
+      acceptable = assetContainers.filter((item) =>
+        extensions.some((ext) => item.asset.name.endsWith(ext))
+      );
     }
+
     if (searchProps.value === "") {
       return acceptable;
     }