Remove: DES-related test, script, and selftest references

[ariwo17]

Description

This PR removes several remaining references to DES from the Mbed TLS core repository as part of the larger DES removal tracked in #9164.

Specifically:

• Removed DES self-test from programs/test/selftest.c
• Removed DES detection logic from tests/compat.sh
• Removed DES mentions from:
  • scripts/config.py (comment only)
  • tests/scripts/analyze_outcomes.py
  • tests/scripts/components-configuration-crypto.sh
  • tests/scripts/components-configuration-tls.sh

This PR does not update changelogs or documentation files. Those will be addressed separately after the full DES removal is complete.

Generated build artifacts (under build/) were not modified or committed.
All tests pass locally.

PR checklist

Please remove the segment/s on either side of the | symbol as appropriate, and add any relevant link/s to the end of the line.
If the provided content is part of the present PR remove the # symbol.

• changelog not required because that will be provided in a follow-up commit after final DES cleanup.
• development PR not required because this is a supporting PR contributing to issue Remove DES #9164.
• TF-PSA-Crypto PR not required because this PR does not touch TF-PSA-Crypto.
• framework PR not required
• 3.6 PR not required because DES removal is only applicable to Mbed TLS 4.0 and later.
• tests not required because no new tests were added; existing tests confirm a clean build.

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