Add orphaned files to gn for src/credentials (#31844)

Author: andy31415

src/credentials/BUILD.gn

@@ -63,7 +63,9 @@ static_library("credentials") {
     "CHIPCert.h",
     "CHIPCertFromX509.cpp",
     "CHIPCertToX509.cpp",
+    "CHIPCert_Internal.h",
     "CHIPCertificateSet.h",
+    "CertificateValidityPolicy.h",
     "CertificationDeclaration.cpp",
     "CertificationDeclaration.h",
     "DeviceAttestationConstructor.cpp",
@@ -76,6 +78,7 @@ static_library("credentials") {
     "GenerateChipX509Cert.cpp",
     "GroupDataProvider.h",
     "GroupDataProviderImpl.cpp",
+    "GroupDataProviderImpl.h",
     "LastKnownGoodTime.cpp",
     "LastKnownGoodTime.h",
     "OperationalCertificateStore.h",