[FIR] Explicit API mode: No REDUNDANT_VISIBILITY_MODIFIER for public

- In explicit API mode, the `public` visibility modifier is not
  redundant unless a declaration is hidden by a container. The
  `REDUNDANT_VISIBILITY_MODIFIER` diagnostic is now not reported in such
  cases.

^KTIJ-24485 fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerFirTestdataTestGenerated.java

@@ -2741,6 +2741,12 @@ public class DiagnosisCompilerFirTestdataTestGenerated extends AbstractDiagnosis
                 runTest("compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierCheckerForInnerComponents.kt");
             }
 
+            @Test
+            @TestMetadata("RedundantVisibilityModifierCheckerWithExplicitApiMode.kt")
+            public void testRedundantVisibilityModifierCheckerWithExplicitApiMode() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierCheckerWithExplicitApiMode.kt");
+            }
+
             @Nested
             @TestMetadata("compiler/fir/analysis-tests/testData/resolve/extendedCheckers/canBeReplacedWithOperatorAssignment")
             @TestDataPath("$PROJECT_ROOT")