RDBC-1082 Fix CustomEntityName test for RavenDB-25738 control-char guard

[M4xymm]

Issue link

https://issues.hibernatingrhinos.com/issue/RDBC-1082

Additional description

This is a cherry-picked commit from v7.2

Type of change

• Bug fix
• Regression bug fix
• Optimization
• New feature

How risky is the change?

• Low
• Moderate
• High
• Not relevant

Backward compatibility

• Non breaking change
• Ensured. Please explain how has it been implemented?
• Breaking change
• Not relevant

Is it platform specific issue?

• Yes. Please list the affected platforms.
• No

Documentation update

• This change requires a documentation update. Please mark the issue on YouTrack using Documentation Required tag.
• No documentation update is needed

Testing by Contributor

• Tests have been added that prove the fix is effective or that the feature works
• Internal classes added to the test class (e.g. entity or index definition classes) have the lowest possible access modifier (preferable private)
• It has been verified by manual testing
• Existing tests verify the correct behavior

Testing by RavenDB QA team

• This change requires a special QA testing due to possible performance or resources usage implications (CPU, memory, IO). Please mark the issue on YouTrack using QA Required tag.
• No special testing by RavenDB QA team is needed

Is there any existing behavior change of other features due to this change?

• Yes. Please list the affected features/subsystems and provide appropriate explanation
• No

UI work

• It requires further work in the Studio. Please mark the issue on YouTrack using Studio Required tag.
• No UI work is needed