fix: Added signing pad disable state while submitting form (#892)

Fixes : #891

apps/web/src/app/(signing)/sign/[token]/form.tsx

@@ -132,6 +132,7 @@ export const SigningForm = ({ document, recipient, fields }: SigningFormProps) =
                   <CardContent className="p-0">
                     <SignaturePad
                       className="h-44 w-full"
+                      disabled={isSubmitting}
                       defaultValue={signature ?? undefined}
                       onChange={(value) => {
                         setSignature(value);