Duplicate empty _node check removed from Subscription.hpp (#23316)

[PavloZMN]

Solved Problem

Duplicate empty node check removal from Subscription.hpp, more details in 23316

Fixes #{23316}

Solution

Refactoring, only subscribe method is used for _node emptiness check.

Changelog Entry

For release notes:

Duplicate empty node check removal from Subscription.hpp

Test coverage

• Unit/integration test: SubscriptionTest.cpp

[PavloZMN]

Hi @sfuhrer,
Can you please take a look on this PR? More details about change specified in issue: 23316

[PavloZMN]

Hi @bresch,
Can you please take a look on this PR, or include into reviewers someone who can make a review?

[PavloZMN]

Hi @dagar,
Can you please take a look on change in this PR?

[PavloZMN]

Hi @sfuhrer,
Can you please include in this PR reviewers someone who can take a look on changes? I don't have permission to do this.

[PavloZMN]

Hi @davids5 ,
Can you please take a look on proposed small performance and code readability improvement?