Bump buildpacks/maven/test-apps/heroku-java-getting-started from `46661f6` to `28a40a6` #911

Job	Run time
Integration Tests (buildpacks/gradle, builder:24, amd64)	2m 30s
Unit Tests	1m 10s
Integration Tests (buildpacks/jvm, builder:24, amd64)	2m 10s
Rust Code Linting	46s
Integration Tests (buildpacks/maven, builder:24, amd64)	2m 48s
Integration Tests (buildpacks/sbt, builder:24, amd64)	4m 36s
Integration Tests (buildpacks/gradle, builder:24, arm64)	4m 28s
Integration Tests (buildpacks/jvm, builder:24, arm64)	2m 53s
Integration Tests (buildpacks/maven, builder:24, arm64)	4m 13s
Integration Tests (buildpacks/sbt, builder:24, arm64)	5m 57s
Integration Tests (buildpacks/gradle, builder:22, amd64)	2m 30s
Integration Tests (buildpacks/jvm, builder:22, amd64)	2m 11s
Integration Tests (buildpacks/jvm-function-invoker, builder:22, amd64)	2m 50s
Integration Tests (buildpacks/maven, builder:22, amd64)	2m 51s
Integration Tests (buildpacks/sbt, builder:22, amd64)	5m 20s
Integration Tests (buildpacks/gradle, builder:20, amd64)	3m 20s
Integration Tests (buildpacks/jvm, builder:20, amd64)	2m 43s
Integration Tests (buildpacks/maven, builder:20, amd64)	4m 0s
Integration Tests (buildpacks/sbt, builder:20, amd64)	5m 20s
	1h 2m 36s

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