fix(deps): update kotlin monorepo to v2.3.21

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
org.jetbrains.kotlin:kotlin-bom (source)	2.3.20 → 2.3.21
org.jetbrains.kotlin:kotlin-gradle-plugin (source)	2.3.20 → 2.3.21

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[codacy-production]

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[github-actions]

SpotBugs

Category	Base	New
Bad practice	6	6
Correctness	24	24
Dodgy code	13	13
Internationalization	2	2
Malicious code vulnerability	11	11
Multithreaded correctness	4	4
Performance	4	4
Security	5	5
Total	69	69