ui2: do not run `npm install` in bot
ui2: do not run `npm install` in bot

This to prevent diff of package-lock.json on bot.

package-lock.json can be changed depends on remote npm server.

Bug: 982254
Change-Id: I10ffc80fefc8708c1e4f193dc68ab0143ab66b9c
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/1833388
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py