fix: ResultEntryRestControllerTest interpretation 500s (#4042)

[VedantMadane]

Summary

Fixes the two ResultEntryRestControllerTest failures reported in #4042 (HTTP 500 on interpretation saves).

Root causes

1. Duplicate interpretation notes – note is not part of result.xml, so interpretation rows accumulate across test methods and NoteServiceImpl.insert throws LIMSDuplicateRecordException (500). Re-saving the same interpretation text in production hit the same path.
2. FHIR mock NPE – test FhirContext is a bare Mockito mock, so newJsonParser() returns null and encode NPEs during result-save FHIR sync (logged as store unavailable).

Changes

• FhirPersistanceServiceImpl: null-safe encodeResourceSafe for trace logs; availability guard before local FHIR transactions (throws checked FhirLocalPersistingException, already swallowed by result-entry callers).
• ResultUtil: skip adding an interpretation note when duplicateNoteExists (same pattern as corrected-result notes).
• ResultEntryRestControllerTest: delete leftover clinlims.note rows for the fixture analyses in @Before.

Test plan

• mvn test -Dtest=ResultEntryRestControllerTest
• Confirm save_withInterpretation_writesReportVisibleNote and save_interpretationFromComponentRow_isScopedToThatComponent return 200

Closes #4042