[milo] Fix Builder page
[milo] Fix Builder page

Turns out Milo has its own BuilderID. Prev CL confused the two.

TBR=tandrii@chromium.org
Change-Id: I00565f0db1b99f94e3e09077629632c62877fe89
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/1662771
Reviewed-by: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>
Commit-Queue: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go