Fix Build and Test CI failures caused by invalid Nextcloud setup cache config and non-testable Xcode scheme

[Copilot]

The Build and Test workflow was failing for two independent reasons: Nextcloud setup was configured with APCu cache settings not available in the job runtime, and xcodebuild test used a scheme not configured for test actions. This PR removes the invalid cache configuration and switches CI to a testable scheme.

• CI stability: Nextcloud setup

  • Removed APCu cache configuration commands from the workflow setup step:
    • memcache.local = \OC\Memcache\APCu
    • memcache.distributed = \OC\Memcache\APCu
  • This avoids occ bootstrap failures when APCu is unavailable in the CI PHP CLI environment.

• CI test execution: Xcode scheme selection

  • Updated workflow env scheme from NextcloudKit to NextcloudKit-Package for xcodebuild test.
  • Aligns test invocation with a scheme that has the test action configured.

env:
  SCHEME: NextcloudKit-Package