refactor: replace signIn callback with signIn event, adjust getUserByEmail in adapter to check provider (#1223)

* refactor: replace signIn callback with signIn event, adjust getUserByEmail in adapter to check provider

* test: adjusting tests for adapter and events

* docs: add comments for unknown auth provider

* fix: missing dayjs import

packages/validation/src/user.ts

@@ -56,7 +56,6 @@ const initUserSchema = createUserSchema;
 const signInSchema = z.object({
   name: z.string().min(1),
   password: z.string().min(1),
-  credentialType: z.enum(["basic", "ldap"]),
 });
 
 const registrationSchema = z