Update bitnami/mysql Docker tag to v8.4.2

This MR contains the following updates:

Package	Type	Update	Change
bitnami/mysql		minor	8.0.39-debian-12-r1 -> 8.4.2-debian-12-r1
bitnami/mysql	ironbank-docker	minor	8.0.39-debian-12-r1 -> 8.4.2-debian-12-r1
bitnami/mysql	stage	minor	8.0.39-debian-12-r1 -> 8.4.2-debian-12-r1

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