Handle null email from Stripe customers

[timkelty]

Description

stripe/sync/customers and stripe/sync/payment-methods can fail because the plugin requires customers have an email but Stripe does not.

❯ ddev craft stripe/sync/customers
Syncing Stripe customers…

Exception 'yii\db\IntegrityException' with message 'SQLSTATE[23502]: Not null violation: 7 ERROR:  null value in column "email" of relation "stripe_customerdata" violates not-null constraint
DETAIL:  Failing row contains (1330, cus_xxx, null, 2024-09-18 21:06:15, {"id": "cus_xxx", "name": null, "email": null, "phone..., 2024-10-11 19:41:30, 2024-10-11 19:41:30, cbb21144-170d-4f9a-9c21-30edb4799035).
The SQL being executed was: INSERT INTO "stripe_customerdata" ("stripeId", "email", "stripeCreated", "data", "dateCreated", "dateUpdated", "uid") VALUES ('cus_QsFZRQdHHB4SV6', NULL, '2024-09-18 21:06:15', '{"id":"cus_xxx","object":"customer","address":null,"balance":0,"created":1726693575,"currency":"usd","default_source":null,"delinquent":false,"description":"(created by Stripe CLI)","discount":null,"email":null,"invoice_prefix":"C9BE1FC5","invoice_settings":{"custom_fields":null,"default_payment_method":null,"footer":null,"rendering_options":null},"livemode":false,"metadata":[],"name":null,"next_invoice_sequence":2,"phone":null,"preferred_locales":[],"shipping":null,"tax_exempt":"none","test_clock":null}'::jsonb, '2024-10-11 19:41:30', '2024-10-11 19:41:30', 'cbb21144-170d-4f9a-9c21-30edb4799035') RETURNING "id"'

❯ ddev craft stripe/sync/payment-methods
Syncing Stripe payment methods…

Exception 'TypeError' with message 'craft\services\Users::getUserByUsernameOrEmail(): Argument #1 ($usernameOrEmail) must be of type string, null given, called in /tmp/packages/craft-stripe/src/services/Api.php on line 132'