Backport 17786 to rec 5.2.x: fix disabling algo 8 also disables DS digest 2

[omoerbeek]

Fixes #17772 in a quick and dirty way.

Proper fix should separate algo handling and digest handling, as more than one algo can use the same digest.

(cherry picked from commit fe26a25)

Backport of #17786

Short description

Checklist

I have:

• read the CONTRIBUTING.md document
• read and accepted the Developer Certificate of Origin document, including the AI Policy, and added a "Signed-off-by" to my commits
• compiled this code
• tested this code
• included documentation (including possible behaviour changes)
• documented the code
• added or modified regression test(s)
• added or modified unit test(s)
• checked that this code was merged to master

[coveralls]

Coverage Report for CI Build 30795283517

Coverage increased (+0.01%) to 66.734%

Details

• Coverage increased (+0.01%) from the base build.
• Patch coverage: 3 of 3 lines across 1 file are fully covered (100%).
• 23 coverage regressions across 8 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

23 previously-covered lines in 8 files lost coverage.

File	Lines Losing Coverage	Coverage
pdns/recursordist/test-syncres_cc1.cc	5	89.71%
pdns/opensslsigners.cc	3	57.4%
pdns/recursordist/pdns_recursor.cc	3	73.6%
pdns/recursordist/syncres.cc	3	80.06%
pdns/recursordist/test-syncres_cc2.cc	3	88.85%
pdns/remote_logger.cc	3	53.13%
pdns/recursordist/aggressive_nsec.cc	2	67.03%
pdns/dnssecinfra.cc	1	54.73%

---

Coverage Stats

Relevant Lines:	78098
Covered Lines:	58797
Line Coverage:	75.29%
Relevant Branches:	36008
Covered Branches:	17350
Branch Coverage:	48.18%
Branches in Coverage %:	Yes
Coverage Strength:	4111937.86 hits per line

---

💛 - Coveralls