[swarming] Be more flexible about id list type
[swarming] Be more flexible about id list type

Change-Id: I56c1db673efaf5d0f55d19b7d5fcb2f63f4a1b9b
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/recipes-py/+/3188070
Commit-Queue: Rob Mohr <d07614a8a0b466db08f68224f87d738b0f9615cf@google.com>
Auto-Submit: Rob Mohr <d07614a8a0b466db08f68224f87d738b0f9615cf@google.com>
Reviewed-by: Yiwei Zhang <50b2a565e2e78c292794832469a30ce5abc9959c@google.com>

luci/recipes-py,luci/recipes-py