style(health): throw IllegalStateException instead of raw Exception (#35602)

Addresses PR #35771 review feedback — a specific unchecked type
communicates intent more clearly than a raw checked Exception. The
surrounding measureExecution(...) machinery still catches it as Exception,
so behavior is unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dsolistorres

dotCMS/src/main/java/com/dotcms/health/checks/cdi/VelocityHealthCheck.java

@@ -84,7 +84,8 @@ protected CheckResult performCheck() throws Exception {
             engine.evaluate(new VelocityContext(), writer, PROBE_LOG_TAG, PROBE_TEMPLATE);
             final String rendered = writer.toString();
             if (rendered.contains(LITERAL_MARKER)) {
-                throw new Exception("Velocity global macro library not registered: "
+                throw new IllegalStateException(
+                        "Velocity global macro library not registered: "
                         + "probe template rendered as literal text. See issues #35329 / #35601.");
             }
             return "Velocity macro library registered (#renderMarks resolved)";