Added toast instead of throwing an error for the case when the amount… (

tldraw#5201)

This PR solves the issue tldraw#5188. Throwing an error for the case when a
user is trying to upload more files than maxFilesAtOnce is replaced with
toast.

_(for testing purposes and screen recording, I reduced the max amount of
files)_

https://github.com/user-attachments/assets/b7468fd0-f14f-41c0-96d9-01f7326a0ecd

P.S.: I'm not sure about the correction of the text, so feel free to
notify me, and I'll change it :)

### Change type

- [x] `bugfix`
- [ ] `improvement`
- [ ] `feature`
- [ ] `api`
- [ ] `other`

### Release notes

- added toast instead of throwing an error for the case when the amount
of files is bigger than `maxFilesAtOnce`

assets/translations/main.json

@@ -120,6 +120,7 @@
 	"assets.files.size-too-big": "File size is too big",
 	"assets.files.type-not-allowed": "File type is not allowed",
 	"assets.files.upload-failed": "Upload failed",
+	"assets.files.amount-too-many": "Too many files",
 	"assets.url.failed": "Couldn’t load URL preview",
 	"theme.dark": "Dark",
 	"theme.light": "Light",