feat: add delete signature function

src/stores/user/signature.ts

@@ -34,5 +34,17 @@ export async function setSignature(image: string) {
 
   if (!userId) return;
 
+  if (image === '') {
+    return await deleteSignature();
+  } else {
     return await api.put('/user/' + userId + '/signature', { data: image });
+  }
+}
+
+export async function deleteSignature() {
+  const userId = getUserId();
+
+  if (!userId) return;
+
+  return await api.delete('/user/' + userId + '/signature');
 }