RFR: 8314656: GHA: No need for Debian ports keyring installation after JDK-8313701

[Aleksey Shipilev]

There is no need for keyring installation after [JDK-8313701](https://bugs.openjdk.org/browse/JDK-8313701). We can simplify that part to reduce the difference between different JDK releases.

Additional testing:
 - [ ] GHA

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/15362/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15362&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314656
  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15362.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15362/head:pull/15362

PR: https://git.openjdk.org/jdk/pull/15362