UI: shorten version on the sidebar
UI: shorten version on the sidebar

Truncate the number of chars shown in the version code.
Realisticlaly for human debugging purposes 5 SHA1 are
unambiguous enough.
Also change the link to point to AOSP, as ui-{canary,stable}
branches are not mirrored onto github.

Change-Id: Icf950051136ea7322d63a276a35d44964345ef47
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto