Reject noerror constraints on EMV2 events 🤖

[lwrage]

Fixes #2817

EMV2 transition conditions accepted {noerror} on typed error events because ErrorModelValidator.checkConditionElementType exempts noerror from type-set containment checks. Reject noerror on every ErrorBehaviorEvent before the existing type checks, with the diagnostic “The noerror constraint is not permitted on an event.” The grammar and metamodel are unchanged.

Issue2817Test covers typed and untyped error events, recovery and repair events, a nested conjunction, and an event in a reusable behavior machine. It checks the diagnostic on each offending condition and the total issue count. A valid model preserves ordinary event constraints and noerror on incoming and subcomponent outgoing propagations. Before the fix, the valid model passed and both negative tests failed because the typed event diagnostic was absent.

Validation:

• Focused regression: 3 tests passed.
• Complete EMV2 test bundle: 296 tests passed, with no failures, errors, or skips.
• Clean root reactor: 143 projects succeeded; 1671 tests across 15 bundles, with 0 failures, 0 errors, and 0 skips.
• git diff --check passed. The regression commit precedes the production fix commit.

Commands run from the repository root:

mvn -o -T5 -s releng/osate.releng/settings.xml -Plocal \
  -pl :org.osate.xtext.aadl2.errormodel,:org.osate.aadl2.errormodel.tests,:org.osate.xtext.aadl2.errormodel.feature \
  -Dtycho.localArtifacts=default -Dpr.build=true -Dsign=false \
  -Dspotbugs=false -Dcodecoverage=false -Djavadoc=false \
  -Dtest=Issue2817Test -DfailIfNoTests=false verify

# Complete EMV2 suite: same options, without -Dtest, using clean verify.

mvn -o -T5 -s releng/osate.releng/settings.xml -Plocal \
  -Dtycho.localArtifacts=ignore -Dpr.build=true -Dsign=false \
  -Dspotbugs=false -Dcodecoverage=false -Djavadoc=false \
  -DfailIfNoTests=false clean install

Targets master with no dependency on unmerged PRs. Risk is limited to the intended validation change: models using noerror on events now report errors; valid propagation conditions retain their existing behavior.