[satlab-ui] Use official Google G icon on Sign in with Google button

Replace the generic login Material icon on the Google Account
Authentication Sign in with Google buttons with the standard 4-color
Google G badge to align with Google Sign-In branding guidelines.

BUG=b:581401180
TEST=npm run compile && ng build --configuration=production && ng test --watch=false

Change-Id: I9e10dfea6c11806f32910f04e433ea9f9b41e277
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/satlab/+/8752162
Auto-Submit: Misha Bilyi <mykhailobilyi@google.com>
Reviewed-by: Tomasz Jakubowski <jakubowskit@google.com>
Tested-by: Misha Bilyi <mykhailobilyi@google.com>
Commit-Queue: Misha Bilyi <mykhailobilyi@google.com>