[macos] suppress swiftc warnings regarding deprecated API (#7989)

==> veertu-anka-vm-clone.template: /Users/<sensitive>/image-generation/add-certificate.swift:21:5: warning: 'SecKeychainSetPreferenceDomain' was deprecated in macOS 10.10: SecKeychain is deprecated
==> veertu-anka-vm-clone.template:     SecKeychainSetPreferenceDomain(SecPreferencesDomain.system)
==> veertu-anka-vm-clone.template:     ^
==> veertu-anka-vm-clone.template: /Users/<sensitive>/image-generation/add-certificate.swift:22:5: warning: result of call to 'deleteCertificateFromKeyChain' is unused
==> veertu-anka-vm-clone.template:     deleteCertificateFromKeyChain(certificateLabel)
==> veertu-anka-vm-clone.template:     ^                            ~~~~~~~~~~~~~~~~~~
==> veertu-anka-vm-clone.template: /Users/<sensitive>/image-generation/add-certificate.swift:36:9: warning: initialization of variable 'status' was never used; consider replacing with assignment to '_' or removing it
==> veertu-anka-vm-clone.template:     var status = SecTrustSettingsSetTrustSettings(certificate, SecTrustSettingsDomain.admin, nil)
==> veertu-anka-vm-clone.template:     ~~~~^~~~~~
==> veertu-anka-vm-clone.template:     _

Author: ilia-shipitsin

images/macos/provision/configuration/configure-machine.sh

@@ -37,7 +37,7 @@ defaults write com.apple.VoiceOver4/default SCREnableAppleScript -bool YES
 # sudo security delete-certificate -Z FF6797793A3CD798DC5B2ABEF56F73EDC9F83A64 /Library/Keychains/System.keychain
 # Big Sur requires user interaction to add a cert https://developer.apple.com/forums/thread/671582, we need to use a workaround with SecItemAdd swift method
 
-swiftc "${HOME}/image-generation/add-certificate.swift"
+swiftc -suppress-warnings "${HOME}/image-generation/add-certificate.swift"
 
 
 certs=(