RFR: 1799: Do not notify on Withdrawn CSR issue

[Zhao Song]

In [SKARA-1714](https://bugs.openjdk.org/browse/SKARA-1714), we will add '(Withdrawn)' to withdrawn CSR issues shown in the pr body. However, this will cause a small bug in the notify bot which the issueNotifier will add a review link to withdrawn CSR issues. To fix this, simply update the filter in the notify/PullRequestWorkItem#parseIssues method.

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Commit messages:
 - SKARA-1799

Changes: https://git.openjdk.org/skara/pull/1460/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1460&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1799
  Stats: 19 lines in 2 files changed: 14 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/skara/pull/1460.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1460/head:pull/1460

PR: https://git.openjdk.org/skara/pull/1460