fix(log4j2): Move super.start() into start(OptionsConfiguration) overload

Ensures the appender is marked as started regardless of which entry
point is used, preventing loggerContext.start() from re-triggering
the no-arg start() and reinitializing Sentry without the test executor.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: romtsn

sentry-log4j2/src/main/java/io/sentry/log4j2/SentryAppender.java

@@ -165,7 +165,6 @@ public SentryAppender(
   @Override
   public void start() {
     start(getOptionsConfiguration(null));
-    super.start();
   }
 
   @NotNull
@@ -203,6 +202,7 @@ void start(final @NotNull Sentry.OptionsConfiguration<SentryOptions> optionsConf
       }
     }
     addPackageAndIntegrationInfo();
+    super.start();
   }
 
   @Override