Correctly parse colours defined as "#..." or "#...." am: 1ec150e514 am: 50808e1afa am: f5ff37cccc

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/layoutlib/+/11476699

Change-Id: I8966e94e4c600601a6a53ef50b9feb5d3f73f219