wrong link for MDC-102 from 101 page

[benhalverson]

https://codelabs.developers.google.com/codelabs/mdc-101-flutter/#2

The link for MDC-102 is an internal go link go/mdc-102-flutter
"product images you'll see in MDC-102."

[lisa-liao]

Thanks for finding this issue. I've updated the link!