Mark ApplicationInfoPropertySource as immutable

Update `ApplicationInfoPropertySource` to indicate it is immutable and
is safe to have mappings cached.

Closes gh-44856

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/ApplicationInfoPropertySource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,8 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.boot.origin.Origin;
+import org.springframework.boot.origin.OriginLookup;
 import org.springframework.boot.system.ApplicationPid;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.MapPropertySource;
@@ -32,7 +34,7 @@
  *
  * @author Moritz Halbritter
  */
-class ApplicationInfoPropertySource extends MapPropertySource {
+class ApplicationInfoPropertySource extends MapPropertySource implements OriginLookup<String> {
 
 	static final String NAME = "applicationInfo";
 
@@ -44,6 +46,16 @@ class ApplicationInfoPropertySource extends MapPropertySource {
 		super(NAME, getProperties(applicationVersion));
 	}
 
+	@Override
+	public Origin getOrigin(String key) {
+		return null;
+	}
+
+	@Override
+	public boolean isImmutable() {
+		return true;
+	}
+
 	private static Map<String, Object> getProperties(String applicationVersion) {
 		Map<String, Object> result = new HashMap<>();
 		if (StringUtils.hasText(applicationVersion)) {