fix(matrix-client/messages-saga): bypass encrypting files during upload if non encrypted room

[domw30]

What does this do?

• This update bypasses the encryption process for file uploads in non-encrypted rooms, optimizing performance and ensuring correct file handling.

Why are we making this change?

• We are making this change to prevent unnecessary encryption in non-encrypted rooms, improving the efficiency of file uploads and maintaining consistent behavior across different room types.

How do I test this?

• run ui and send images in non encrypted rooms then refresh

Key decisions and Risk Assessment:

Things to consider:

1. How will this affect security?
2. How will this affect performance?
3. Does this change any APIs?