Add more unit tests for the class of `YamlTransactionRuleConfigurationSwapper`

[FlyingZC]

Hi community, This issue is for #20305

Aim

Add more unit tests for the class of org.apache.shardingsphere.transaction.yaml.swapper.YamlTransactionRuleConfigurationSwapper.

Basic Qualifications

• Java
• Maven
• Transaction

Detail

You can mock the transaction configuration and assert the result of swapToYamlConfiguration method.You can refer to this class org.apache.shardingsphere.authority.yaml.swapper.YamlAuthorityRuleConfigurationSwapperTest to write unit tests.