test: fix TypeScript validation tests errors

[wolfy1339]

Ever since new events were added in #1189, the validation tests have started failing

I added 2 missing tests that were not added in #924

These are the errors:

Property 'foo' does not exist on type 'EmitterWebhookEvent'.
  Property 'foo' does not exist on type 'BaseWebhookEvent<"branch_protection_configuration">'.

Expression produces a union type that is too complex to represent.

Property 'foo' does not exist on type 'BaseWebhookEvent<"branch_protection_configuration"> | BaseWebhookEvent<"branch_protection_rule"> | BaseWebhookEvent<"check_run"> | ... 320 more ... | (BaseWebhookEvent<...> & { ...; })'.
  Property 'foo' does not exist on type 'BaseWebhookEvent<"branch_protection_configuration">'.

[github-actions]

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