[BUG] Signature component fires change event with `modified = false` on user input

Describe the bug modified flag in onChange handler is supposed to indicate whether the change was made by a user, however in the case of signature component it always fires with false

To Reproduce Steps to reproduce the behavior:

1. Go to sandbox
2. Open console
3. Draw on signature component
4. Console logs false for modified even though it was changed due to user input

Expected behavior modified to be true when signature component was changed by user input

Sandbox Example Sandbox example

Desktop (please complete the following information):

• OS: MacOS
• Browser: Chrome