Remove outdated reference to ApplicationNameConverter

Closes gh-46364

Author: snicoll

spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/logback/defaults.xml

@@ -5,7 +5,6 @@ Default logback configuration provided for import
 -->
 
 <included>
-	<conversionRule conversionWord="applicationName" class="org.springframework.boot.logging.logback.ApplicationNameConverter"/>
 	<conversionRule conversionWord="clr" class="org.springframework.boot.logging.logback.ColorConverter"/>
 	<conversionRule conversionWord="correlationId" class="org.springframework.boot.logging.logback.CorrelationIdConverter"/>
 	<conversionRule conversionWord="esb" class="org.springframework.boot.logging.logback.EnclosedInSquareBracketsConverter" />