Disable 7.17 DRA packaging from Jenkins (#39428) (#39432)

This commit disables triggering DRA packaging builds for the 7.17 branch via Jenkins.

(cherry picked from commit f4a984d)

Co-authored-by: Dimitrios Liappis <dimitrios.liappis@gmail.com>

.ci/jobs/packaging.yml

@@ -13,8 +13,8 @@
  discover-pr-forks-strategy: 'merge-current'
  discover-pr-forks-trust: 'permission'
  discover-pr-origin: 'merge-current'
- discover-tags: true
- head-filter-regex: '(7\.17|PR-.*)'
+ discover-tags: false
+ head-filter-regex: '(PR-.*)'
  disable-pr-notifications: true
  notification-context: 'beats-packaging'
  repo: 'beats'
@@ -27,10 +27,6 @@
  - tags:
  ignore-tags-older-than: -1
  ignore-tags-newer-than: 30
- - named-branches:
- - regex-name:
- regex: '7\.17'
- case-sensitive: true
  - change-request:
  ignore-target-only-changes: true
  clean: