add unit tests for EncryptColumnExistedReviser.java

[Sakshi-75]

Fixes #28548

Changes proposed in this pull request:

Added unit tests for EncryptColumnExistedReviser.java

---

Before committing this PR, I'm sure that I have checked the following options:

• My code follows the code of conduct of this project.
• I have self-reviewed the commit code.
• I have (or in comment I request) added corresponding labels for the pull request.
• I have passed maven check locally : ./mvnw clean install -B -T1C -Dmaven.javadoc.skip -Dmaven.jacoco.skip -e.
• I have made corresponding changes to the documentation.
• I have added corresponding unit tests for my changes.

[tuichenchuxin]

@Sakshi-75 please fix ci

[Sakshi-75]

@Sakshi-75 please fix ci

Hi @tuichenchuxin fixed