Polish 'Simplify stream chain operations'

See gh-39259

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/IncompatibleConfigurationFailureAnalyzer.java

@@ -16,8 +16,6 @@
 
 package org.springframework.boot.context.properties;
 
-import java.util.stream.Collectors;
-
 import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
 import org.springframework.boot.diagnostics.FailureAnalysis;