RFR: 2508: IssueNotifier should handle inactive JBS users [v2]

[Zhao Song]

> This patch is trying to let IssueNotifier skip setting the assignee to an inactive user, otherwise, the bot will be stuck.

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

  update copyright

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Changes:
  - all: https://git.openjdk.org/skara/pull/1720/files
  - new: https://git.openjdk.org/skara/pull/1720/files/84106573..89a8f499

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1720&range=01
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1720&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/skara/pull/1720.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1720/head:pull/1720

PR: https://git.openjdk.org/skara/pull/1720