Optimized the partitioning strategy implementation details to avoid unnecessarily high RU usage

[FabianMeiswinkel]

Description

This PR optimizes some of the partitioning strategy values to reduce chance that RU-consumption for queries or change feed requests is unnecessarily high when no EPK filtering is enabled for an account. Functionally using Spark partitions scoped to subsets of physical partitions is possible to increase parallelization but it comes with an overhead of increase RU usage - and in many cases that is unnecessary. So, this PR avoids this from happening in most cases (unless partition merge happened) for all partitioning strategies except for Aggressive and Custom.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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Testing Guidelines

• Pull request includes test coverage for the included changes.

[xinlian12]

LGTM, thanks

[kushagraThapar]

Changes look good, however, I am wondering if this is a breaking change? And should we explicitly call it out in the changelog instead of calling it out as optimized?

[FabianMeiswinkel]

/azp run java - cosmos - spark

[azure-pipelines]

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