SET IFEQ command implemented in Java + tests

[Maayanshani25]

Issue link

This Pull Request is linked to issue (URL): [/issues/2811]

Description

This pull Request is implemented the IFEQ option in the SET commamnd. Tests were added, and docstring to the command and the related method.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one issue.
• Commit message has a detailed description of what changed and why.
• Tests are added or updated.
• CHANGELOG.md and documentation files are updated.
• Destination branch is correct - main or release
• Create merge commit if merging release branch into main, squash otherwise.

[Maayanshani25]

@Yury-Fridlyand
I found the implementation of java a bit different than node.
Do you think it's possible to this the also here? #2909 (comment)

[Yury-Fridlyand]

Java is not so flexible, unfortunately.
But it is still possible to do if you customize the setter in the SetOptions builder. Probably, you can keep exposed ConditionalSet with 2 options, but under the hood have another one with 3 options.
Need to be careful to avoid breaking changes while doing refactoring.
StandaloneSubscriptionConfigurationBuilder is a nice example of a customized builder.