FINERACT-2165: Migrate SavingsAccountChargeRoundingTest to Feign

[Dhanno98]

Description

Part of FINERACT-2165 system-wide migration of integration tests to fineract-client-feign.

Migrates SavingsAccountChargeRoundingTest from the legacy Fineract client to the Fineract Feign Client.

The migration:

• Updates savings product and savings account setup to use the Feign test helpers.
• Migrates savings account charge creation, application, and retrieval to the Feign client.
• Migrates savings account deposits, withdrawals, and account retrieval to the Feign client.
• Adds the required savings charge and business-date helpers to the Feign savings test infrastructure.
• Preserves the existing test scenarios and assertions without changing their intended behavior.

All existing SavingsAccountChargeRoundingTest scenarios pass after the migration.

Checklist

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