Bump Kotlin to 1.9.21 and make use of `data object` #1215

Job	Run time
Build apps (Foss, Debug, app)	5m 27s
Lint vitals (Foss, Beta, app)	5m 26s
Unit tests (Debug, test)	3m 16s
Build apps (Gplay, Debug, app)	5m 19s
Lint vitals (Foss, Release, app)	5m 32s
Unit tests (Debug, testFoss)	5m 35s
Lint vitals (Gplay, Beta, app)	5m 27s
Unit tests (Debug, testGplay)	5m 32s
Lint vitals (Gplay, Release, app)	5m 32s
Unit tests (Beta, test)	3m 26s
Unit tests (Beta, testFoss)	5m 33s
Unit tests (Beta, testGplay)	5m 41s
Unit tests (Release, test)	3m 22s
Unit tests (Release, testFoss)	5m 40s
Unit tests (Release, testGplay)	5m 29s
	1h 16m 17s

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