ClientAwareness headers in v12 applied only when setting them in defaultContext

Describe the bug

When configuring ClientAwareness headers in apollo-angular v12, they only will become applied to the request when configuring them in the query context or by configuring them globally in the defaultContext. But the regular way to configure them directly in the ApolloClient.Options like before v12, doesn't work anymore:

provideApollo(() => ({
  link: inject(HttpLink).create({
    uri: '/graphql',
    withCredentials: true
  }),
  cache: new InMemoryCache(),
  clientAwareness: { // <-- this is the regular place to configure clientAwareness which worked before v12
    name: 'my-client-name',
    version: 'dev.0.0.1'
  },
  defaultContext: {
    clientAwareness: {  // <-- only when adding the clientAwareness config here, the related headers will become applied 
      name: 'my-client-name',
      version: 'dev.0.0.1'
    }
  }
}));

Expected behavior

clientAwareness configuration should be applied when adding them to the default location in ApolloClient.Options as before v12

Environment:

- @angular/cli@20.3.9
- @angular/core@20.3.10
- @apollo/client@4.0.9
- apollo-angular@12.1.0
- graphql@16.10.0
- typescript@5.9.3

Start by reproducing the configuration shown in the issue and trace how clientAwareness is handled in ApolloClient.Options versus defaultContext. Verify the request headers produced by each configuration, then add or update coverage for the regular clientAwareness option so the expected headers are applied without defaultContext.