Support dynamic indices with more granular time-based partitions

Is your feature request related to a problem? Please describe.
As a user of the OpenSearch sink, I would like to roll over my indices with custom time durations, rather than just those provided by the JavaDateTime format (https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html). For example, I would like to either roll over indices every 2 days, or every 6 hours, instead of being forced to use granularity of 1 day or 1 hour only.

Describe the solution you'd like
The ability to create dynamic indices and rollover with specific time patterns, but without the restriction of using a multiple of 1 for hours and days.

Describe alternatives you've considered (Optional)
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

Start by tracing the OpenSearch sink's dynamic-index and rollover entry points, then review how JavaDateTime currently determines time-based granularity. Done means users can configure non-unit durations such as two days or six hours without the current one-day or one-hour restriction, with behavior verified by the relevant tests.