Revert "Upgrade to Spring Boot 2.4.6"

[Artur-]

Reverts #553

At least in some cases this causes the app not to start with

15:05:40.490 [restartedMain] ERROR org.springframework.boot.SpringApplication - Application run failed
java.lang.IllegalStateException: No subdirectories found for mandatory directory location 'file:./config/*/'.
	at org.springframework.util.Assert.state(Assert.java:76)
	at org.springframework.boot.context.config.StandardConfigDataLocationResolver.resolvePatternEmptyDirectories(StandardConfigDataLocationResolver.java:268)
	at org.springframework.boot.context.config.StandardConfigDataLocationResolver.resolveEmptyDirectories(StandardConfigDataLocationResolver.java:257)

[Artur-]

See spring-projects/spring-boot#26627 on why 2.4.6 does not work. 2.4.7 should fix it